Chapter 1 - Key Terms

abdominopelvic cavity

division of the anterior (ventral) cavity that houses the abdominal and pelvic viscera

anabolism

assembly of more complex molecules from simpler molecules

anatomical position

standard reference position used for describing locations and directions on the human body

anatomy

science that studies the form and composition of the body’s structures

anterior

describes the front or direction toward the front of the body; also referred to as ventral

anterior cavity

larger body cavity located anterior to the posterior (dorsal) body cavity; includes the serous membrane-lined pleural cavities for the lungs, pericardial cavity for the heart, and peritoneal cavity for the abdominal and pelvic organs; also referred to as ventral cavity

catabolism

breaking down of more complex molecules into simpler molecules

caudal

describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal column); also referred to as inferior

cell

smallest independently functioning unit of all organisms; in animals, a cell contains cytoplasm, composed of fluid and organelles

computed tomography (CT)

medical imaging technique in which a computer-enhanced cross-sectional X-ray image is obtained

control center

compares values to their normal range; deviations cause the activation of an effector

cranial

describes a position above or higher than another part of the body proper; also referred to as superior

cranial cavity

division of the posterior (dorsal) cavity that houses the brain

deep

describes a position farther from the surface of the body

development

changes an organism goes through during its life

differentiation

process by which unspecialized cells become specialized in structure and function

distal

describes a position farther from the point of attachment or the trunk of the body

dorsal

describes the back or direction toward the back of the body; also referred to as posterior

dorsal cavity

posterior body cavity that houses the brain and spinal cord; also referred to the posterior body cavity

effector

organ that can cause a change in a value

frontal plane

two-dimensional, vertical plane that divides the body or organ into anterior and posterior portions

gross anatomy

study of the larger structures of the body, typically with the unaided eye; also referred to macroscopic anatomy

growth

process of increasing in size

homeostasis

steady state of body systems that living organisms maintain

inferior

describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal column); also referred to as caudal

lateral

describes the side or direction toward the side of the body

magnetic resonance imaging (MRI)

medical imaging technique in which a device generates a magnetic field to obtain detailed sectional images of the internal structures of the body

medial

describes the middle or direction toward the middle of the body

metabolism

sum of all of the body’s chemical reactions

microscopic anatomy

study of very small structures of the body using magnification

negative feedback

homeostatic mechanism that tends to stabilize an upset in the body’s physiological condition by preventing an excessive response to a stimulus, typically as the stimulus is removed

normal range

range of values around the set point that do not cause a reaction by the control center

nutrient

chemical obtained from foods and beverages that is critical to human survival

organ

functionally distinct structure composed of two or more types of tissues

organ system

group of organs that work together to carry out a particular function

organism

living being that has a cellular structure and that can independently perform all physiologic functions necessary for life

pericardium

sac that encloses the heart

peritoneum

serous membrane that lines the abdominopelvic cavity and covers the organs found there

physiology

science that studies the chemistry, biochemistry, and physics of the body’s functions

plane

imaginary two-dimensional surface that passes through the body

pleura

serous membrane that lines the pleural cavity and covers the lungs

positive feedback

mechanism that intensifies a change in the body’s physiological condition in response to a stimulus

positron emission tomography (PET)

medical imaging technique in which radiopharmaceuticals are traced to reveal metabolic and physiological functions in tissues

posterior

describes the back or direction toward the back of the body; also referred to as dorsal

posterior cavity

posterior body cavity that houses the brain and spinal cord; also referred to as dorsal cavity

pressure

force exerted by a substance in contact with another substance

prone

face down

proximal

describes a position nearer to the point of attachment or the trunk of the body

regional anatomy

study of the structures that contribute to specific body regions

renewal

process by which worn-out cells are replaced

reproduction

process by which new organisms are generated

responsiveness

ability of an organisms or a system to adjust to changes in conditions

sagittal plane

two-dimensional, vertical plane that divides the body or organ into right and left sides

section

in anatomy, a single flat surface of a three-dimensional structure that has been cut through

sensor

(also, receptor) reports a monitored physiological value to the control center

serosa

membrane that covers organs and reduces friction; also referred to as serous membrane

serous membrane

membrane that covers organs and reduces friction; also referred to as serosa

set point

ideal value for a physiological parameter; the level or small range within which a physiological parameter such as blood pressure is stable and optimally healthful, that is, within its parameters of homeostasis

spinal cavity

division of the dorsal cavity that houses the spinal cord; also referred to as vertebral cavity

superficial

describes a position nearer to the surface of the body

superior

describes a position above or higher than another part of the body proper; also referred to as cranial

supine

face up

systemic anatomy

study of the structures that contribute to specific body systems

thoracic cavity

division of the anterior (ventral) cavity that houses the heart, lungs, esophagus, and trachea

tissue

group of similar or closely related cells that act together to perform a specific function

transverse plane

two-dimensional, horizontal plane that divides the body or organ into superior and inferior portions

ultrasonography

application of ultrasonic waves to visualize subcutaneous body structures such as tendons and organs

ventral

describes the front or direction toward the front of the body; also referred to as anterior

ventral cavity

larger body cavity located anterior to the posterior (dorsal) body cavity; includes the serous membrane-lined pleural cavities for the lungs, pericardial cavity for the heart, and peritoneal cavity for the abdominal and pelvic organs; also referred to as anterior body cavity

X-ray

form of high energy electromagnetic radiation with a short wavelength capable of penetrating solids and ionizing gases; used in medicine as a diagnostic aid to visualize body structures such as bones

Chapter 2 - Key Terms

acid

compound that releases hydrogen ions (H+) in solution

activation energy

amount of energy greater than the energy contained in the reactants, which must be overcome for a reaction to proceed

adenosine triphosphate (ATP)

nucleotide containing ribose and an adenine base that is essential in energy transfer

amino acid

building block of proteins; characterized by an amino and carboxyl functional groups and a variable side-chain

anion

atom with a negative charge

atom

smallest unit of an element that retains the unique properties of that element

atomic number

number of protons in the nucleus of an atom

base

compound that accepts hydrogen ions (H+) in solution

bond

electrical force linking atoms

buffer

solution containing a weak acid or a weak base that opposes wide fluctuations in the pH of body fluids

carbohydrate

class of organic compounds built from sugars, molecules containing carbon, hydrogen, and oxygen in a 1-2-1 ratio

catalyst

substance that increases the rate of a chemical reaction without itself being changed in the process

cation

atom with a positive charge

chemical energy

form of energy that is absorbed as chemical bonds form, stored as they are maintained, and released as they are broken

colloid

liquid mixture in which the solute particles consist of clumps of molecules large enough to scatter light

compound

substance composed of two or more different elements joined by chemical bonds

concentration

number of particles within a given space

covalent bond

chemical bond in which two atoms share electrons, thereby completing their valence shells

decomposition reaction

type of catabolic reaction in which one or more bonds within a larger molecule are broken, resulting in the release of smaller molecules or atoms

denaturation

change in the structure of a molecule through physical or chemical means

deoxyribonucleic acid (DNA)

deoxyribose-containing nucleotide that stores genetic information

disaccharide

pair of carbohydrate monomers bonded by dehydration synthesis via a glycosidic bond

disulfide bond

covalent bond formed within a polypeptide between sulfide groups of sulfur-containing amino acids, for example, cysteine

electron

subatomic particle having a negative charge and nearly no mass; found orbiting the atom’s nucleus

electron shell

area of space a given distance from an atom’s nucleus in which electrons are grouped

element

substance that cannot be created or broken down by ordinary chemical means

enzyme

protein or RNA that catalyzes chemical reactions

exchange reaction

type of chemical reaction in which bonds are both formed and broken, resulting in the transfer of components

functional group

group of atoms linked by strong covalent bonds that tends to behave as a distinct unit in chemical reactions with other atoms

hydrogen bond

dipole-dipole bond in which a hydrogen atom covalently bonded to an electronegative atom is weakly attracted to a second electronegative atom

inorganic compound

substance that does not contain both carbon and hydrogen

ion

atom with an overall positive or negative charge

ionic bond

attraction between an anion and a cation

isotope

one of the variations of an element in which the number of neutrons differ from each other

kinetic energy

energy that matter possesses because of its motion

lipid

class of nonpolar organic compounds built from hydrocarbons and distinguished by the fact that they are not soluble in water

macromolecule

large molecule formed by covalent bonding

mass number

sum of the number of protons and neutrons in the nucleus of an atom

matter

physical substance; that which occupies space and has mass

molecule

two or more atoms covalently bonded together

monosaccharide

monomer of carbohydrate; also known as a simple sugar

neutron

heavy subatomic particle having no electrical charge and found in the atom’s nucleus

nucleotide

class of organic compounds composed of one or more phosphate groups, a pentose sugar, and a base

organic compound

substance that contains both carbon and hydrogen

peptide bond

covalent bond formed by dehydration synthesis between two amino acids

periodic table of the elements

arrangement of the elements in a table according to their atomic number; elements having similar properties because of their electron arrangements compose columns in the table, while elements having the same number of valence shells compose rows in the table

pH

negative logarithm of the hydrogen ion (H+) concentration of a solution

phospholipid

a lipid compound in which a phosphate group is combined with a diglyceride

phosphorylation

addition of one or more phosphate groups to an organic compound

polar molecule

molecule with regions that have opposite charges resulting from uneven numbers of electrons in the nuclei of the atoms participating in the covalent bond

polysaccharide

compound consisting of more than two carbohydrate monomers bonded by dehydration synthesis via glycosidic bonds

potential energy

stored energy matter possesses because of the positioning or structure of its components

product

one or more substances produced by a chemical reaction

prostaglandin

lipid compound derived from fatty acid chains and important in regulating several body processes

protein

class of organic compounds that are composed of many amino acids linked together by peptide bonds

proton

heavy subatomic particle having a positive charge and found in the atom’s nucleus

purine

nitrogen-containing base with a double ring structure; adenine and guanine

pyrimidine

nitrogen-containing base with a single ring structure; cytosine, thiamine, and uracil

radioactive isotope

unstable, heavy isotope that gives off subatomic particles, or electromagnetic energy, as it decays; also called radioisotopes

reactant

one or more substances that enter into the reaction

ribonucleic acid (RNA)

ribose-containing nucleotide that helps manifest the genetic code as protein

solution

homogeneous liquid mixture in which a solute is dissolved into molecules within a solvent

steroid

(also, sterol) lipid compound composed of four hydrocarbon rings bonded to a variety of other atoms and molecules

substrate

reactant in an enzymatic reaction

suspension

liquid mixture in which particles distributed in the liquid settle out over time

synthesis reaction

type of anabolic reaction in which two or more atoms or molecules bond, resulting in the formation of a larger molecule

triglyceride

lipid compound composed of a glycerol molecule bonded with three fatty acid chains

valence shell

outermost electron shell of an atom

Chapter 3 - Key Terms

active transport

form of transport across the cell membrane that requires input of cellular energy

amphipathic

describes a molecule that exhibits a difference in polarity between its two ends, resulting in a difference in water solubility

anaphase

third stage of mitosis (and meiosis), during which sister chromatids separate into two new nuclear regions of a dividing cell

anticodon

consecutive sequence of three nucleotides on a tRNA molecule that is complementary to a specific codon on an mRNA molecule

autolysis

breakdown of cells by their own enzymatic action

autophagy

lysosomal breakdown of a cell’s own components

cell cycle

life cycle of a single cell, from its birth until its division into two new daughter cells

cell membrane

membrane surrounding all animal cells, composed of a lipid bilayer interspersed with various molecules; also known as plasma membrane

centriole

small, self-replicating organelle that provides the origin for microtubule growth and moves DNA during cell division

centromere

region of attachment for two sister chromatids

centrosome

cellular structure that organizes microtubules during cell division

channel protein

membrane-spanning protein that has an inner pore which allows the passage of one or more substances

checkpoint

progress point in the cell cycle during which certain conditions must be met in order for the cell to proceed to a subsequence phase

chromatin

substance consisting of DNA and associated proteins

chromosome

condensed version of chromatin

cilia

small appendage on certain cells formed by microtubules and modified for movement of materials across the cellular surface

cleavage furrow

contractile ring that forms around a cell during cytokinesis that pinches the cell into two halves

codon

consecutive sequence of three nucleotides on an mRNA molecule that corresponds to a specific amino acid

concentration gradient

difference in the concentration of a substance between two regions

cyclin

one of a group of proteins that function in the progression of the cell cycle

cyclin-dependent kinase (CDK)

one of a group of enzymes associated with cyclins that help them perform their functions

cytokinesis

final stage in cell division, where the cytoplasm divides to form two separate daughter cells

cytoplasm

internal material between the cell membrane and nucleus of a cell, mainly consisting of a water-based fluid called cytosol, within which are all the other organelles and cellular solute and suspended materials

cytoskeleton

“skeleton” of a cell; formed by rod-like proteins that support the cell’s shape and provide, among other functions, locomotive abilities

cytosol

clear, semi-fluid medium of the cytoplasm, made up mostly of water

diffusion

movement of a substance from an area of higher concentration to one of lower concentration

diploid

condition marked by the presence of a double complement of genetic material (two sets of chromosomes, one set inherited from each of two parents)

DNA polymerase

enzyme that functions in adding new nucleotides to a growing strand of DNA during DNA replication

DNA replication

process of duplicating a molecule of DNA

electrical gradient

difference in the electrical charge (potential) between two regions

endocytosis

import of material into the cell by formation of a membrane-bound vesicle

endoplasmic reticulum (ER)

cellular organelle that consists of interconnected membrane-bound tubules, which may or may not be associated with ribosomes (rough type or smooth type, respectively)

exocytosis

export of a substance out of a cell by formation of a membrane-bound vesicle

exon

one of the coding regions of an mRNA molecule that remain after splicing

extracellular fluid (ECF)

fluid exterior to cells; includes the interstitial fluid, blood plasma, and fluid found in other reservoirs in the body

facilitated diffusion

diffusion of a substance with the aid of a membrane protein

flagellum

appendage on certain cells formed by microtubules and modified for movement

G0 phase

phase of the cell cycle, usually entered from the G1 phase; characterized by long or permanent periods where the cell does not move forward into the DNA synthesis phase

G1 phase

first phase of the cell cycle, after a new cell is born

G2 phase

third phase of the cell cycle, after the DNA synthesis phase

gene

functional length of DNA that provides the genetic information necessary to build a protein

gene expression

active interpretation of the information coded in a gene to produce a functional gene product

genome

entire complement of an organism’s DNA; found within virtually every cell

glycocalyx

coating of sugar molecules that surrounds the cell membrane

glycoprotein

protein that has one or more carbohydrates attached

Golgi apparatus

cellular organelle formed by a series of flattened, membrane-bound sacs that functions in protein modification, tagging, packaging, and transport

helicase

enzyme that functions to separate the two DNA strands of a double helix during DNA replication

histone

family of proteins that associate with DNA in the nucleus to form chromatin

homologous

describes two copies of the same chromosome (not identical), one inherited from each parent

hydrophilic

describes a substance or structure attracted to water

hydrophobic

describes a substance or structure repelled by water

hypertonic

describes a solution concentration that is higher than a reference concentration

hypotonic

describes a solution concentration that is lower than a reference concentration

integral protein

membrane-associated protein that spans the entire width of the lipid bilayer

intermediate filament

type of cytoskeletal filament made of keratin, characterized by an intermediate thickness, and playing a role in resisting cellular tension

interphase

entire life cycle of a cell, excluding mitosis

interstitial fluid (IF)

fluid in the small spaces between cells not contained within blood vessels

intracellular fluid (ICF)

fluid in the cytosol of cells

intron

non-coding regions of a pre-mRNA transcript that may be removed during splicing

isotonic

describes a solution concentration that is the same as a reference concentration

kinetochore

region of a centromere where microtubules attach to a pair of sister chromatids

ligand

molecule that binds with specificity to a specific receptor molecule

lysosome

membrane-bound cellular organelle originating from the Golgi apparatus and containing digestive enzymes

messenger RNA (mRNA)

nucleotide molecule that serves as an intermediate in the genetic code between DNA and protein

metaphase

second stage of mitosis (and meiosis), characterized by the linear alignment of sister chromatids in the center of the cell

metaphase plate

linear alignment of sister chromatids in the center of the cell, which takes place during metaphase

microfilament

the thinnest of the cytoskeletal filaments; composed of actin subunits that function in muscle contraction and cellular structural support

microtubule

the thickest of the cytoskeletal filaments, composed of tubulin subunits that function in cellular movement and structural support

mitochondrion

one of the cellular organelles bound by a double lipid bilayer that function primarily in the production of cellular energy (ATP)

mitosis

division of genetic material, during which the cell nucleus breaks down and two new, fully functional, nuclei are formed

mitotic phase

phase of the cell cycle in which a cell undergoes mitosis

mitotic spindle

network of microtubules, originating from centrioles, that arranges and pulls apart chromosomes during mitosis

multipotent

describes the condition of being able to differentiate into different types of cells within a given cell lineage or small number of lineages, such as a red blood cell or white blood cell

mutation

change in the nucleotide sequence in a gene within a cell’s DNA

nuclear envelope

membrane that surrounds the nucleus; consisting of a double lipid-bilayer

nuclear pore

one of the small, protein-lined openings found scattered throughout the nuclear envelope

nucleolus

small region of the nucleus that functions in ribosome synthesis

nucleosome

unit of chromatin consisting of a DNA strand wrapped around histone proteins

nucleus

cell’s central organelle; contains the cell’s DNA

oligopotent

describes the condition of being more specialized than multipotency; the condition of being able to differentiate into one of a few possible cell types

organelle

any of several different types of membrane-enclosed specialized structures in the cell that perform specific functions for the cell

osmosis

diffusion of water molecules down their concentration gradient across a selectively permeable membrane

passive transport

form of transport across the cell membrane that does not require input of cellular energy

peripheral protein

membrane-associated protein that does not span the width of the lipid bilayer, but is attached peripherally to integral proteins, membrane lipids, or other components of the membrane

peroxisome

membrane-bound organelle that contains enzymes primarily responsible for detoxifying harmful substances

phagocytosis

endocytosis of large particles

pinocytosis

endocytosis of fluid

pluripotent

describes the condition of being able to differentiate into a large variety of cell types

polypeptide

chain of amino acids linked by peptide bonds

polyribosome

simultaneous translation of a single mRNA transcript by multiple ribosomes

promoter

region of DNA that signals transcription to begin at that site within the gene

prophase

first stage of mitosis (and meiosis), characterized by breakdown of the nuclear envelope and condensing of the chromatin to form chromosomes

proteome

full complement of proteins produced by a cell (determined by the cell’s specific gene expression)

reactive oxygen species (ROS)

a group of extremely reactive peroxides and oxygen-containing radicals that may contribute to cellular damage

receptor

protein molecule that contains a binding site for another specific molecule (called a ligand)

receptor-mediated endocytosis

endocytosis of ligands attached to membrane-bound receptors

ribosomal RNA (rRNA)

RNA that makes up the subunits of a ribosome

ribosome

cellular organelle that functions in protein synthesis

RNA polymerase

enzyme that unwinds DNA and then adds new nucleotides to a growing strand of RNA for the transcription phase of protein synthesis

S phase

stage of the cell cycle during which DNA replication occurs

selective permeability

feature of any barrier that allows certain substances to cross but excludes others

sister chromatid

one of a pair of identical chromosomes, formed during DNA replication

sodium-potassium pump

(also, Na+/K+ ATP-ase) membrane-embedded protein pump that uses ATP to move Na+ out of a cell and K+ into the cell

somatic cell

all cells of the body excluding gamete cells

spliceosome

complex of enzymes that serves to splice out the introns of a pre-mRNA transcript

splicing

the process of modifying a pre-mRNA transcript by removing certain, typically non-coding, regions

stem cell

cell that is oligo-, multi-, or pleuripotent that has the ability to produce additional stem cells rather than becoming further specialized

telophase

final stage of mitosis (and meiosis), preceding cytokinesis, characterized by the formation of two new daughter nuclei

totipotent

embryonic cells that have the ability to differentiate into any type of cell and organ in the body

transcription

process of producing an mRNA molecule that is complementary to a particular gene of DNA

transcription factor

one of the proteins that regulate the transcription of genes

transfer RNA (tRNA)

molecules of RNA that serve to bring amino acids to a growing polypeptide strand and properly place them into the sequence

translation

process of producing a protein from the nucleotide sequence code of an mRNA transcript

triplet

consecutive sequence of three nucleotides on a DNA molecule that, when transcribed into an mRNA codon, corresponds to a particular amino acid

unipotent

describes the condition of being committed to a single specialized cell type

vesicle

membrane-bound structure that contains materials within or outside of the cell

Chapter 4 - Key Terms

adipocytes

lipid storage cells

adipose tissue

specialized areolar tissue rich in stored fat

anchoring junction

mechanically attaches adjacent cells to each other or to the basement membrane

apical

that part of a cell or tissue which, in general, faces an open space

apocrine secretion

release of a substance along with the apical portion of the cell

apoptosis

programmed cell death

areolar tissue

(also, loose connective tissue) a type of connective tissue proper that shows little specialization with cells dispersed in the matrix

astrocyte

star-shaped cell in the central nervous system that regulates ions and uptake and/or breakdown of some neurotransmitters and contributes to the formation of the blood-brain barrier

atrophy

loss of mass and function

basal lamina

thin extracellular layer that lies underneath epithelial cells and separates them from other tissues

basement membrane

in epithelial tissue, a thin layer of fibrous material that anchors the epithelial tissue to the underlying connective tissue; made up of the basal lamina and reticular lamina

cardiac muscle

heart muscle, under involuntary control, composed of striated cells that attach to form fibers, each cell contains a single nucleus, contracts autonomously

cell junction

point of cell-to-cell contact that connects one cell to another in a tissue

chondrocytes

cells of the cartilage

clotting

also called coagulation; complex process by which blood components form a plug to stop bleeding

collagen fiber

flexible fibrous proteins that give connective tissue tensile strength

connective tissue

type of tissue that serves to hold in place, connect, and integrate the body’s organs and systems

connective tissue membrane

connective tissue that encapsulates organs and lines movable joints

connective tissue proper

connective tissue containing a viscous matrix, fibers, and cells.

cutaneous membrane

skin; epithelial tissue made up of a stratified squamous epithelial cells that cover the outside of the body

dense connective tissue

connective tissue proper that contains many fibers that provide both elasticity and protection

ectoderm

outermost embryonic germ layer from which the epidermis and the nervous tissue derive

elastic cartilage

type of cartilage, with elastin as the major protein, characterized by rigid support as well as elasticity

elastic fiber

fibrous protein within connective tissue that contains a high percentage of the protein elastin that allows the fibers to stretch and return to original size

endocrine gland

groups of cells that release chemical signals into the intercellular fluid to be picked up and transported to their target organs by blood

endoderm

innermost embryonic germ layer from which most of the digestive system and lower respiratory system derive

endothelium

tissue that lines vessels of the lymphatic and cardiovascular system, made up of a simple squamous epithelium

epithelial membrane

epithelium attached to a layer of connective tissue

epithelial tissue

type of tissue that serves primarily as a covering or lining of body parts, protecting the body; it also functions in absorption, transport, and secretion

exocrine gland

group of epithelial cells that secrete substances through ducts that open to the skin or to internal body surfaces that lead to the exterior of the body

fibroblast

most abundant cell type in connective tissue, secretes protein fibers and matrix into the extracellular space

fibrocartilage

tough form of cartilage, made of thick bundles of collagen fibers embedded in chondroitin sulfate ground substance

fibrocyte

less active form of fibroblast

fluid connective tissue

specialized cells that circulate in a watery fluid containing salts, nutrients, and dissolved proteins

gap junction

allows cytoplasmic communications to occur between cells

goblet cell

unicellular gland found in columnar epithelium that secretes mucous

ground substance

fluid or semi-fluid portion of the matrix

histamine

chemical compound released by mast cells in response to injury that causes vasodilation and endothelium permeability

histology

microscopic study of tissue architecture, organization, and function

holocrine secretion

release of a substance caused by the rupture of a gland cell, which becomes part of the secretion

hyaline cartilage

most common type of cartilage, smooth and made of short collagen fibers embedded in a chondroitin sulfate ground substance

inflammation

response of tissue to injury

lacunae

(singular = lacuna) small spaces in bone or cartilage tissue that cells occupy

lamina propria

areolar connective tissue underlying a mucous membrane

loose connective tissue

(also, areolar tissue) type of connective tissue proper that shows little specialization with cells dispersed in the matrix

matrix

extracellular material which is produced by the cells embedded in it, containing ground substance and fibers

merocrine secretion

release of a substance from a gland via exocytosis

mesenchymal cell

adult stem cell from which most connective tissue cells are derived

mesenchyme

embryonic tissue from which connective tissue cells derive

mesoderm

middle embryonic germ layer from which connective tissue, muscle tissue, and some epithelial tissue derive

mesothelium

simple squamous epithelial tissue which covers the major body cavities and is the epithelial portion of serous membranes

mucous connective tissue

specialized loose connective tissue present in the umbilical cord

mucous gland

group of cells that secrete mucous, a thick, slippery substance that keeps tissues moist and acts as a lubricant

mucous membrane

tissue membrane that is covered by protective mucous and lines tissue exposed to the outside environment

muscle tissue

type of tissue that is capable of contracting and generating tension in response to stimulation; produces movement.

myelin

layer of lipid inside some neuroglial cells that wraps around the axons of some neurons

myocyte

muscle cells

necrosis

accidental death of cells and tissues

nervous tissue

type of tissue that is capable of sending and receiving impulses through electrochemical signals.

neuroglia

supportive neural cells

neuron

excitable neural cell that transfer nerve impulses

oligodendrocyte

neuroglial cell that produces myelin in the brain

parenchyma

functional cells of a gland or organ, in contrast with the supportive or connective tissue of a gland or organ

primary union

condition of a wound where the wound edges are close enough to be brought together and fastened if necessary, allowing quicker and more thorough healing

pseudostratified columnar epithelium

tissue that consists of a single layer of irregularly shaped and sized cells that give the appearance of multiple layers; found in ducts of certain glands and the upper respiratory tract

reticular fiber

fine fibrous protein, made of collagen subunits, which cross-link to form supporting “nets” within connective tissue

reticular lamina

matrix containing collagen and elastin secreted by connective tissue; a component of the basement membrane

reticular tissue

type of loose connective tissue that provides a supportive framework to soft organs, such as lymphatic tissue, spleen, and the liver

Schwann cell

neuroglial cell that produces myelin in the peripheral nervous system

secondary union

wound healing facilitated by wound contraction

serous gland

group of cells within the serous membrane that secrete a lubricating substance onto the surface

serous membrane

type of tissue membrane that lines body cavities and lubricates them with serous fluid

simple columnar epithelium

tissue that consists of a single layer of column-like cells; promotes secretion and absorption in tissues and organs

simple cuboidal epithelium

tissue that consists of a single layer of cube-shaped cells; promotes secretion and absorption in ducts and tubules

simple squamous epithelium

tissue that consists of a single layer of flat scale-like cells; promotes diffusion and filtration across surface

skeletal muscle

usually attached to bone, under voluntary control, each cell is a fiber that is multinucleated and striated

smooth muscle

under involuntary control, moves internal organs, cells contain a single nucleus, are spindle-shaped, and do not appear striated; each cell is a fiber

stratified columnar epithelium

tissue that consists of two or more layers of column-like cells, contains glands and is found in some ducts

stratified cuboidal epithelium

tissue that consists of two or more layers of cube-shaped cells, found in some ducts

stratified squamous epithelium

tissue that consists of multiple layers of cells with the most apical being flat scale-like cells; protects surfaces from abrasion

striation

alignment of parallel actin and myosin filaments which form a banded pattern

supportive connective tissue

type of connective tissue that provides strength to the body and protects soft tissue

synovial membrane

connective tissue membrane that lines the cavities of freely movable joints, producing synovial fluid for lubrication

tight junction

forms an impermeable barrier between cells

tissue

group of cells that are similar in form and perform related functions

tissue membrane

thin layer or sheet of cells that covers the outside of the body, organs, and internal cavities

totipotent

embryonic cells that have the ability to differentiate into any type of cell and organ in the body

transitional epithelium

form of stratified epithelium found in the urinary tract, characterized by an apical layer of cells that change shape in response to the presence of urine

vasodilation

widening of blood vessels

wound contraction

process whereby the borders of a wound are physically drawn together

Chapter 5 - Key Terms

acne

skin condition due to infected sebaceous glands

albinism

genetic disorder that affects the skin, in which there is no melanin production

anagen

active phase of the hair growth cycle

apocrine sweat gland

type of sweat gland that is associated with hair follicles in the armpits and genital regions

arrector pili

smooth muscle that is activated in response to external stimuli that pull on hair follicles and make the hair “stand up”

basal cell

type of stem cell found in the stratum basale and in the hair matrix that continually undergoes cell division, producing the keratinocytes of the epidermis

basal cell carcinoma

cancer that originates from basal cells in the epidermis of the skin

bedsore

sore on the skin that develops when regions of the body start necrotizing due to constant pressure and lack of blood supply; also called decubitis ulcers

callus

thickened area of skin that arises due to constant abrasion

catagen

transitional phase marking the end of the anagen phase of the hair growth cycle

corn

type of callus that is named for its shape and the elliptical motion of the abrasive force

cortex

in hair, the second or middle layer of keratinocytes originating from the hair matrix, as seen in a cross-section of the hair bulb

cuticle

in hair, the outermost layer of keratinocytes originating from the hair matrix, as seen in a cross-section of the hair bulb

dermal papilla

(plural = dermal papillae) extension of the papillary layer of the dermis that increases surface contact between the epidermis and dermis

dermis

layer of skin between the epidermis and hypodermis, composed mainly of connective tissue and containing blood vessels, hair follicles, sweat glands, and other structures

desmosome

structure that forms an impermeable junction between cells

eccrine sweat gland

type of sweat gland that is common throughout the skin surface; it produces a hypotonic sweat for thermoregulation

eczema

skin condition due to an allergic reaction, which resembles a rash

elastin fibers

fibers made of the protein elastin that increase the elasticity of the dermis

eleiden

clear protein-bound lipid found in the stratum lucidum that is derived from keratohyalin and helps to prevent water loss

epidermis

outermost tissue layer of the skin

eponychium

nail fold that meets the proximal end of the nail body, also called the cuticle

external root sheath

outer layer of the hair follicle that is an extension of the epidermis, which encloses the hair root

first-degree burn

superficial burn that injures only the epidermis

fourth-degree burn

burn in which full thickness of the skin and underlying muscle and bone is damaged

glassy membrane

layer of connective tissue that surrounds the base of the hair follicle, connecting it to the dermis

hair

keratinous filament growing out of the epidermis

hair bulb

structure at the base of the hair root that surrounds the dermal papilla

hair follicle

cavity or sac from which hair originates

hair matrix

layer of basal cells from which a strand of hair grows

hair papilla

mass of connective tissue, blood capillaries, and nerve endings at the base of the hair follicle

hair root

part of hair that is below the epidermis anchored to the follicle

hair shaft

part of hair that is above the epidermis but is not anchored to the follicle

hypodermis

connective tissue connecting the integument to the underlying bone and muscle

hyponychium

thickened layer of stratum corneum that lies below the free edge of the nail

integumentary system

skin and its accessory structures

internal root sheath

innermost layer of keratinocytes in the hair follicle that surround the hair root up to the hair shaft

keloid

type of scar that has layers raised above the skin surface

keratin

type of structural protein that gives skin, hair, and nails its hard, water-resistant properties

keratinocyte

cell that produces keratin and is the most predominant type of cell found in the epidermis

keratohyalin

granulated protein found in the stratum granulosum

Langerhans cell

specialized dendritic cell found in the stratum spinosum that functions as a macrophage

lunula

basal part of the nail body that consists of a crescent-shaped layer of thick epithelium

medulla

in hair, the innermost layer of keratinocytes originating from the hair matrix

Meissner corpuscle

(also, tactile corpuscle) receptor in the skin that responds to light touch

melanin

pigment that determines the color of hair and skin

melanocyte

cell found in the stratum basale of the epidermis that produces the pigment melanin

melanoma

type of skin cancer that originates from the melanocytes of the skin

melanosome

intercellular vesicle that transfers melanin from melanocytes into keratinocytes of the epidermis

Merkel cell

receptor cell in the stratum basale of the epidermis that responds to the sense of touch

metastasis

spread of cancer cells from a source to other parts of the body

nail bed

layer of epidermis upon which the nail body forms

nail body

main keratinous plate that forms the nail

nail cuticle

fold of epithelium that extends over the nail bed, also called the eponychium

nail fold

fold of epithelium at that extend over the sides of the nail body, holding it in place

nail root

part of the nail that is lodged deep in the epidermis from which the nail grows

Pacinian corpuscle

(also, lamellated corpuscle) receptor in the skin that responds to vibration

papillary layer

superficial layer of the dermis, made of loose, areolar connective tissue

reticular layer

deeper layer of the dermis; it has a reticulated appearance due to the presence of abundant collagen and elastin fibers

rickets

disease in children caused by vitamin D deficiency, which leads to the weakening of bones

scar

collagen-rich skin formed after the process of wound healing that is different from normal skin

sebaceous gland

type of oil gland found in the dermis all over the body and helps to lubricate and waterproof the skin and hair by secreting sebum

sebum

oily substance that is composed of a mixture of lipids that lubricates the skin and hair

second-degree burn

partial-thickness burn that injures the epidermis and a portion of the dermis

squamous cell carcinoma

type of skin cancer that originates from the stratum spinosum of the epidermis

stratum basale

deepest layer of the epidermis, made of epidermal stem cells

stratum corneum

most superficial layer of the epidermis

stratum granulosum

layer of the epidermis superficial to the stratum spinosum

stratum lucidum

layer of the epidermis between the stratum granulosum and stratum corneum, found only in thick skin covering the palms, soles of the feet, and digits

stratum spinosum

layer of the epidermis superficial to the stratum basale, characterized by the presence of desmosomes

stretch mark

mark formed on the skin due to a sudden growth spurt and expansion of the dermis beyond its elastic limits

sudoriferous gland

sweat gland

telogen

resting phase of the hair growth cycle initiated with catagen and terminated by the beginning of a new anagen phase of hair growth

third-degree burn

burn that penetrates and destroys the full thickness of the skin (epidermis and dermis)

vitamin D

compound that aids absorption of calcium and phosphates in the intestine to improve bone health

vitiligo

skin condition in which melanocytes in certain areas lose the ability to produce melanin, possibly due an autoimmune reaction that leads to loss of color in patches

Chapter 6 - Key Terms

articular cartilage

thin layer of cartilage covering an epiphysis; reduces friction and acts as a shock absorber

articulation

where two bone surfaces meet

bone

hard, dense connective tissue that forms the structural elements of the skeleton

canaliculi

(singular = canaliculus) channels within the bone matrix that house one of an osteocyte’s many cytoplasmic extensions that it uses to communicate and receive nutrients

cartilage

semi-rigid connective tissue found on the skeleton in areas where flexibility and smooth surfaces support movement

central canal

longitudinal channel in the center of each osteon; contains blood vessels, nerves, and lymphatic vessels; also known as the Haversian canal

closed reduction

manual manipulation of a broken bone to set it into its natural position without surgery

compact bone

dense osseous tissue that can withstand compressive forces

diaphysis

tubular shaft that runs between the proximal and distal ends of a long bone

diploë

layer of spongy bone, that is sandwiched between two the layers of compact bone found in flat bones

endochondral ossification

process in which bone forms by replacing hyaline cartilage

endosteum

delicate membranous lining of a bone’s medullary cavity

epiphyseal line

completely ossified remnant of the epiphyseal plate

epiphyseal plate

(also, growth plate) sheet of hyaline cartilage in the metaphysis of an immature bone; replaced by bone tissue as the organ grows in length

epiphysis

wide section at each end of a long bone; filled with spongy bone and red marrow

external callus

collar of hyaline cartilage and bone that forms around the outside of a fracture

flat bone

thin and curved bone; serves as a point of attachment for muscles and protects internal organs

fracture

broken bone

fracture hematoma

blood clot that forms at the site of a broken bone

hematopoiesis

production of blood cells, which occurs in the red marrow of the bones

hole

opening or depression in a bone

hypercalcemia

condition characterized by abnormally high levels of calcium

hypocalcemia

condition characterized by abnormally low levels of calcium

internal callus

fibrocartilaginous matrix, in the endosteal region, between the two ends of a broken bone

intramembranous ossification

process by which bone forms directly from mesenchymal tissue

irregular bone

bone of complex shape; protects internal organs from compressive forces

lacunae

(singular = lacuna) spaces in a bone that house an osteocyte

long bone

cylinder-shaped bone that is longer than it is wide; functions as a lever

medullary cavity

hollow region of the diaphysis; filled with yellow marrow

modeling

process, during bone growth, by which bone is resorbed on one surface of a bone and deposited on another

nutrient foramen

small opening in the middle of the external surface of the diaphysis, through which an artery enters the bone to provide nourishment

open reduction

surgical exposure of a bone to reset a fracture

orthopedist

doctor who specializes in diagnosing and treating musculoskeletal disorders and injuries

osseous tissue

bone tissue; a hard, dense connective tissue that forms the structural elements of the skeleton

ossification

(also, osteogenesis) bone formation

ossification center

cluster of osteoblasts found in the early stages of intramembranous ossification

osteoblast

cell responsible for forming new bone

osteoclast

cell responsible for resorbing bone

osteocyte

primary cell in mature bone; responsible for maintaining the matrix

osteogenic cell

undifferentiated cell with high mitotic activity; the only bone cells that divide; they differentiate and develop into osteoblasts

osteoid

uncalcified bone matrix secreted by osteoblasts

osteon

(also, Haversian system) basic structural unit of compact bone; made of concentric layers of calcified matrix

osteoporosis

disease characterized by a decrease in bone mass; occurs when the rate of bone resorption exceeds the rate of bone formation, a common occurrence as the body ages

perforating canal

(also, Volkmann’s canal) channel that branches off from the central canal and houses vessels and nerves that extend to the periosteum and endosteum

perichondrium

membrane that covers cartilage

periosteum

fibrous membrane covering the outer surface of bone and continuous with ligaments

primary ossification center

region, deep in the periosteal collar, where bone development starts during endochondral ossification

projection

bone markings where part of the surface sticks out above the rest of the surface, where tendons and ligaments attach

proliferative zone

region of the epiphyseal plate that makes new chondrocytes to replace those that die at the diaphyseal end of the plate and contributes to longitudinal growth of the epiphyseal plate

red marrow

connective tissue in the interior cavity of a bone where hematopoiesis takes place

remodeling

process by which osteoclasts resorb old or damaged bone at the same time as and on the same surface where osteoblasts form new bone to replace that which is resorbed

reserve zone

region of the epiphyseal plate that anchors the plate to the osseous tissue of the epiphysis

secondary ossification center

region of bone development in the epiphyses

sesamoid bone

small, round bone embedded in a tendon; protects the tendon from compressive forces

short bone

cube-shaped bone that is approximately equal in length, width, and thickness; provides limited motion

skeletal system

organ system composed of bones and cartilage that provides for movement, support, and protection

spongy bone

(also, cancellous bone) trabeculated osseous tissue that supports shifts in weight distribution

trabeculae

(singular = trabecula) spikes or sections of the lattice-like matrix in spongy bone

yellow marrow

connective tissue in the interior cavity of a bone where fat is stored

zone of calcified matrix

region of the epiphyseal plate closest to the diaphyseal end; functions to connect the epiphyseal plate to the diaphysis

zone of maturation and hypertrophy

region of the epiphyseal plate where chondrocytes from the proliferative zone grow and mature and contribute to the longitudinal growth of the epiphyseal plate

Chapter 7 - Key Terms

alveolar process of the mandible

upper border of mandibular body that contains the lower teeth

alveolar process of the maxilla

curved, inferior margin of the maxilla that supports and anchors the upper teeth

angle of the mandible

rounded corner located at outside margin of the body and ramus junction

angle of the rib

portion of rib with greatest curvature; together, the rib angles form the most posterior extent of the thoracic cage

anterior (ventral) sacral foramen

one of the series of paired openings located on the anterior (ventral) side of the sacrum

anterior arch

anterior portion of the ring-like C1 (atlas) vertebra

anterior cranial fossa

shallowest and most anterior cranial fossa of the cranial base that extends from the frontal bone to the lesser wing of the sphenoid bone

anterior longitudinal ligament

ligament that runs the length of the vertebral column, uniting the anterior aspects of the vertebral bodies

anulus fibrosus

tough, fibrous outer portion of an intervertebral disc, which is strongly anchored to the bodies of the adjacent vertebrae

appendicular skeleton

all bones of the upper and lower limbs, plus the girdle bones that attach each limb to the axial skeleton

articular tubercle

smooth ridge located on the inferior skull, immediately anterior to the mandibular fossa

atlas

first cervical (C1) vertebra

axial skeleton

central, vertical axis of the body, including the skull, vertebral column, and thoracic cage

axis

second cervical (C2) vertebra

body of the rib

shaft portion of a rib

brain case

portion of the skull that contains and protects the brain, consisting of the eight bones that form the cranial base and rounded upper skull

calvaria

(also, skullcap) rounded top of the skull

carotid canal

zig-zag tunnel providing passage through the base of the skull for the internal carotid artery to the brain; begins anteromedial to the styloid process and terminates in the middle cranial cavity, near the posterior-lateral base of the sella turcica

cervical curve

posteriorly concave curvature of the cervical vertebral column region; a secondary curve of the vertebral column

cervical vertebrae

seven vertebrae numbered as C1–C7 that are located in the neck region of the vertebral column

clavicular notch

paired notches located on the superior-lateral sides of the sternal manubrium, for articulation with the clavicle

coccyx

small bone located at inferior end of the adult vertebral column that is formed by the fusion of four coccygeal vertebrae; also referred to as the “tailbone”

condylar process of the mandible

thickened upward projection from posterior margin of mandibular ramus

condyle

oval-shaped process located at the top of the condylar process of the mandible

coronal suture

joint that unites the frontal bone to the right and left parietal bones across the top of the skull

coronoid process of the mandible

flattened upward projection from the anterior margin of the mandibular ramus

costal cartilage

hyaline cartilage structure attached to the anterior end of each rib that provides for either direct or indirect attachment of most ribs to the sternum

costal facet

site on the lateral sides of a thoracic vertebra for articulation with the head of a rib

costal groove

shallow groove along the inferior margin of a rib that provides passage for blood vessels and a nerve

cranial cavity

interior space of the skull that houses the brain

cranium

skull

cribriform plate

small, flattened areas with numerous small openings, located to either side of the midline in the floor of the anterior cranial fossa; formed by the ethmoid bone

crista galli

small upward projection located at the midline in the floor of the anterior cranial fossa; formed by the ethmoid bone

dens

bony projection (odontoid process) that extends upward from the body of the C2 (axis) vertebra

ear ossicles

three small bones located in the middle ear cavity that serve to transmit sound vibrations to the inner ear

ethmoid air cell

one of several small, air-filled spaces located within the lateral sides of the ethmoid bone, between the orbit and upper nasal cavity

ethmoid bone

unpaired bone that forms the roof and upper, lateral walls of the nasal cavity, portions of the floor of the anterior cranial fossa and medial wall of orbit, and the upper portion of the nasal septum

external acoustic meatus

ear canal opening located on the lateral side of the skull

external occipital protuberance

small bump located at the midline on the posterior skull

facet

small, flattened area on a bone for an articulation (joint) with another bone, or for muscle attachment

facial bones

fourteen bones that support the facial structures and form the upper and lower jaws and the hard palate

false ribs

vertebrochondral ribs 8–12 whose costal cartilage either attaches indirectly to the sternum via the costal cartilage of the next higher rib or does not attach to the sternum at all

floating ribs

vertebral ribs 11–12 that do not attach to the sternum or to the costal cartilage of another rib

fontanelle

expanded area of fibrous connective tissue that separates the brain case bones of the skull prior to birth and during the first year after birth

foramen lacerum

irregular opening in the base of the skull, located inferior to the exit of carotid canal

foramen magnum

large opening in the occipital bone of the skull through which the spinal cord emerges and the vertebral arteries enter the cranium

foramen ovale of the middle cranial fossa

oval-shaped opening in the floor of the middle cranial fossa

foramen rotundum

round opening in the floor of the middle cranial fossa, located between the superior orbital fissure and foramen ovale

foramen spinosum

small opening in the floor of the middle cranial fossa, located lateral to the foramen ovale

frontal bone

unpaired bone that forms forehead, roof of orbit, and floor of anterior cranial fossa

frontal sinus

air-filled space within the frontal bone; most anterior of the paranasal sinuses

glabella

slight depression of frontal bone, located at the midline between the eyebrows

greater wings of sphenoid bone

lateral projections of the sphenoid bone that form the anterior wall of the middle cranial fossa and an area of the lateral skull

hard palate

bony structure that forms the roof of the mouth and floor of the nasal cavity, formed by the palatine process of the maxillary bones and the horizontal plate of the palatine bones

head of the rib

posterior end of a rib that articulates with the bodies of thoracic vertebrae

horizontal plate

medial extension from the palatine bone that forms the posterior quarter of the hard palate

hyoid bone

small, U-shaped bone located in upper neck that does not contact any other bone

hypoglossal canal

paired openings that pass anteriorly from the anterior-lateral margins of the foramen magnum deep to the occipital condyles

hypophyseal (pituitary) fossa

shallow depression on top of the sella turcica that houses the pituitary (hypophyseal) gland

inferior articular process

bony process that extends downward from the vertebral arch of a vertebra that articulates with the superior articular process of the next lower vertebra

inferior nasal concha

one of the paired bones that project from the lateral walls of the nasal cavity to form the largest and most inferior of the nasal conchae

infraorbital foramen

opening located on anterior skull, below the orbit

infratemporal fossa

space on lateral side of skull, below the level of the zygomatic arch and deep (medial) to the ramus of the mandible

internal acoustic meatus

opening into petrous ridge, located on the lateral wall of the posterior cranial fossa

intervertebral disc

structure located between the bodies of adjacent vertebrae that strongly joins the vertebrae; provides padding, weight bearing ability, and enables vertebral column movements

intervertebral foramen

opening located between adjacent vertebrae for exit of a spinal nerve

jugular (suprasternal) notch

shallow notch located on superior surface of sternal manubrium

jugular foramen

irregularly shaped opening located in the lateral floor of the posterior cranial cavity

kyphosis

(also, humpback or hunchback) excessive posterior curvature of the thoracic vertebral column region

lacrimal bone

paired bones that contribute to the anterior-medial wall of each orbit

lacrimal fossa

shallow depression in the anterior-medial wall of the orbit, formed by the lacrimal bone that gives rise to the nasolacrimal canal

lambdoid suture

inverted V-shaped joint that unites the occipital bone to the right and left parietal bones on the posterior skull

lamina

portion of the vertebral arch on each vertebra that extends between the transverse and spinous process

lateral pterygoid plate

paired, flattened bony projections of the sphenoid bone located on the inferior skull, lateral to the medial pterygoid plate

lateral sacral crest

paired irregular ridges running down the lateral sides of the posterior sacrum that was formed by the fusion of the transverse processes from the five sacral vertebrae

lesser wings of the sphenoid bone

lateral extensions of the sphenoid bone that form the bony lip separating the anterior and middle cranial fossae

ligamentum flavum

series of short ligaments that unite the lamina of adjacent vertebrae

lingula

small flap of bone located on the inner (medial) surface of mandibular ramus, next to the mandibular foramen

lordosis

(also, swayback) excessive anterior curvature of the lumbar vertebral column region

lumbar curve

posteriorly concave curvature of the lumbar vertebral column region; a secondary curve of the vertebral column

lumbar vertebrae

five vertebrae numbered as L1–L5 that are located in lumbar region (lower back) of the vertebral column

mandible

unpaired bone that forms the lower jaw bone; the only moveable bone of the skull

mandibular foramen

opening located on the inner (medial) surface of the mandibular ramus

mandibular fossa

oval depression located on the inferior surface of the skull

mandibular notch

large U-shaped notch located between the condylar process and coronoid process of the mandible

manubrium

expanded, superior portion of the sternum

mastoid process

large bony prominence on the inferior, lateral skull, just behind the earlobe

maxillary bone

(also, maxilla) paired bones that form the upper jaw and anterior portion of the hard palate

maxillary sinus

air-filled space located with each maxillary bone; largest of the paranasal sinuses

medial pterygoid plate

paired, flattened bony projections of the sphenoid bone located on the inferior skull medial to the lateral pterygoid plate; form the posterior portion of the nasal cavity lateral wall

median sacral crest

irregular ridge running down the midline of the posterior sacrum that was formed from the fusion of the spinous processes of the five sacral vertebrae

mental foramen

opening located on the anterior-lateral side of the mandibular body

mental protuberance

inferior margin of anterior mandible that forms the chin

middle cranial fossa

centrally located cranial fossa that extends from the lesser wings of the sphenoid bone to the petrous ridge

middle nasal concha

nasal concha formed by the ethmoid bone that is located between the superior and inferior conchae

mylohyoid line

bony ridge located along the inner (medial) surface of the mandibular body

nasal bone

paired bones that form the base of the nose

nasal cavity

opening through skull for passage of air

nasal conchae

curved bony plates that project from the lateral walls of the nasal cavity; include the superior and middle nasal conchae, which are parts of the ethmoid bone, and the independent inferior nasal conchae bone

nasal septum

flat, midline structure that divides the nasal cavity into halves, formed by the perpendicular plate of the ethmoid bone, vomer bone, and septal cartilage

nasolacrimal canal

passage for drainage of tears that extends downward from the medial-anterior orbit to the nasal cavity, terminating behind the inferior nasal conchae

neck of the rib

narrowed region of a rib, next to the rib head

notochord

rod-like structure along dorsal side of the early embryo; largely disappears during later development but does contribute to formation of the intervertebral discs

nuchal ligament

expanded portion of the supraspinous ligament within the posterior neck; interconnects the spinous processes of the cervical vertebrae and attaches to the base of the skull

nucleus pulposus

gel-like central region of an intervertebral disc; provides for padding, weight-bearing, and movement between adjacent vertebrae

occipital bone

unpaired bone that forms the posterior portions of the brain case and base of the skull

occipital condyle

paired, oval-shaped bony knobs located on the inferior skull, to either side of the foramen magnum

optic canal

opening spanning between middle cranial fossa and posterior orbit

orbit

bony socket that contains the eyeball and associated muscles

palatine bone

paired bones that form the posterior quarter of the hard palate and a small area in floor of the orbit

palatine process

medial projection from the maxilla bone that forms the anterior three quarters of the hard palate

paranasal sinuses

cavities within the skull that are connected to the conchae that serve to warm and humidify incoming air, produce mucus, and lighten the weight of the skull; consist of frontal, maxillary, sphenoidal, and ethmoidal sinuses

parietal bone

paired bones that form the upper, lateral sides of the skull

pedicle

portion of the vertebral arch that extends from the vertebral body to the transverse process

perpendicular plate of the ethmoid bone

downward, midline extension of the ethmoid bone that forms the superior portion of the nasal septum

petrous ridge

petrous portion of the temporal bone that forms a large, triangular ridge in the floor of the cranial cavity, separating the middle and posterior cranial fossae; houses the middle and inner ear structures

posterior (dorsal) sacral foramen

one of the series of paired openings located on the posterior (dorsal) side of the sacrum

posterior arch

posterior portion of the ring-like C1 (atlas) vertebra

posterior cranial fossa

deepest and most posterior cranial fossa; extends from the petrous ridge to the occipital bone

posterior longitudinal ligament

ligament that runs the length of the vertebral column, uniting the posterior sides of the vertebral bodies

primary curve

anteriorly concave curvatures of the thoracic and sacrococcygeal regions that are retained from the original fetal curvature of the vertebral column

pterion

H-shaped suture junction region that unites the frontal, parietal, temporal, and sphenoid bones on the lateral side of the skull

ramus of the mandible

vertical portion of the mandible

ribs

thin, curved bones of the chest wall

sacral canal

bony tunnel that runs through the sacrum

sacral foramina

series of paired openings for nerve exit located on both the anterior (ventral) and posterior (dorsal) aspects of the sacrum

sacral hiatus

inferior opening and termination of the sacral canal

sacral promontory

anterior lip of the base (superior end) of the sacrum

sacrococcygeal curve

anteriorly concave curvature formed by the sacrum and coccyx; a primary curve of the vertebral column

sacrum

single bone located near the inferior end of the adult vertebral column that is formed by the fusion of five sacral vertebrae; forms the posterior portion of the pelvis

sagittal suture

joint that unites the right and left parietal bones at the midline along the top of the skull

sclerotome

medial portion of a somite consisting of mesenchyme tissue that will give rise to bone, cartilage, and fibrous connective tissues

scoliosis

abnormal lateral curvature of the vertebral column

secondary curve

posteriorly concave curvatures of the cervical and lumbar regions of the vertebral column that develop after the time of birth

sella turcica

elevated area of sphenoid bone located at midline of the middle cranial fossa

septal cartilage

flat cartilage structure that forms the anterior portion of the nasal septum

skeleton

bones of the body

skull

bony structure that forms the head, face, and jaws, and protects the brain; consists of 22 bones

somite

one of the paired, repeating blocks of tissue located on either side of the notochord in the early embryo

sphenoid bone

unpaired bone that forms the central base of skull

sphenoid sinus

air-filled space located within the sphenoid bone; most posterior of the paranasal sinuses

spinous process

unpaired bony process that extends posteriorly from the vertebral arch of a vertebra

squamous suture

joint that unites the parietal bone to the squamous portion of the temporal bone on the lateral side of the skull

sternal angle

junction line between manubrium and body of the sternum and the site for attachment of the second rib to the sternum

sternum

flattened bone located at the center of the anterior chest

styloid process

downward projecting, elongated bony process located on the inferior aspect of the skull

stylomastoid foramen

opening located on inferior skull, between the styloid process and mastoid process

superior articular process

bony process that extends upward from the vertebral arch of a vertebra that articulates with the inferior articular process of the next higher vertebra

superior articular process of the sacrum

paired processes that extend upward from the sacrum to articulate (join) with the inferior articular processes from the L5 vertebra

superior nasal concha

smallest and most superiorly located of the nasal conchae; formed by the ethmoid bone

superior nuchal line

paired bony lines on the posterior skull that extend laterally from the external occipital protuberance

superior orbital fissure

irregularly shaped opening between the middle cranial fossa and the posterior orbit

supraorbital foramen

opening located on anterior skull, at the superior margin of the orbit

supraorbital margin

superior margin of the orbit

supraspinous ligament

ligament that interconnects the spinous processes of the thoracic and lumbar vertebrae

suture

junction line at which adjacent bones of the skull are united by fibrous connective tissue

temporal bone

paired bones that form the lateral, inferior portions of the skull, with squamous, mastoid, and petrous portions

temporal fossa

shallow space on the lateral side of the skull, above the level of the zygomatic arch

temporal process of the zygomatic bone

short extension from the zygomatic bone that forms the anterior portion of the zygomatic arch

thoracic cage

consists of 12 pairs of ribs and sternum

thoracic curve

anteriorly concave curvature of the thoracic vertebral column region; a primary curve of the vertebral column

thoracic vertebrae

twelve vertebrae numbered as T1–T12 that are located in the thoracic region (upper back) of the vertebral column

transverse foramen

opening found only in the transverse processes of cervical vertebrae

transverse process

paired bony processes that extends laterally from the vertebral arch of a vertebra

true ribs

vertebrosternal ribs 1–7 that attach via their costal cartilage directly to the sternum

tubercle of the rib

small bump on the posterior side of a rib for articulation with the transverse process of a thoracic vertebra

vertebra

individual bone in the neck and back regions of the vertebral column

vertebral (spinal) canal

bony passageway within the vertebral column for the spinal cord that is formed by the series of individual vertebral foramina

vertebral arch

bony arch formed by the posterior portion of each vertebra that surrounds and protects the spinal cord

vertebral column

entire sequence of bones that extend from the skull to the tailbone

vertebral foramen

opening associated with each vertebra defined by the vertebral arch that provides passage for the spinal cord

vomer bone

unpaired bone that forms the inferior and posterior portions of the nasal septum

xiphoid process

small process that forms the inferior tip of the sternum

zygomatic arch

elongated, free-standing arch on the lateral skull, formed anteriorly by the temporal process of the zygomatic bone and posteriorly by the zygomatic process of the temporal bone

zygomatic bone

cheekbone; paired bones that contribute to the lateral orbit and anterior zygomatic arch

zygomatic process of the temporal bone

extension from the temporal bone that forms the posterior portion of the zygomatic arch

Chapter 8 - Key Terms

acetabulum

large, cup-shaped cavity located on the lateral side of the hip bone; formed by the junction of the ilium, pubis, and ischium portions of the hip bone

acromial end of the clavicle

lateral end of the clavicle that articulates with the acromion of the scapula

acromial process

acromion of the scapula

acromioclavicular joint

articulation between the acromion of the scapula and the acromial end of the clavicle

acromion

flattened bony process that extends laterally from the scapular spine to form the bony tip of the shoulder

adductor tubercle

small, bony bump located on the superior aspect of the medial epicondyle of the femur

anatomical neck

line on the humerus located around the outside margin of the humeral head

ankle joint

joint that separates the leg and foot portions of the lower limb; formed by the articulations between the talus bone of the foot inferiorly, and the distal end of the tibia, medial malleolus of the tibia, and lateral malleolus of the fibula superiorly

anterior border of the tibia

narrow, anterior margin of the tibia that extends inferiorly from the tibial tuberosity

anterior inferior iliac spine

small, bony projection located on the anterior margin of the ilium, below the anterior superior iliac spine

anterior sacroiliac ligament

strong ligament between the sacrum and the ilium portions of the hip bone that supports the anterior side of the sacroiliac joint

anterior superior iliac spine

rounded, anterior end of the iliac crest

apical ectodermal ridge

enlarged ridge of ectoderm at the distal end of a limb bud that stimulates growth and elongation of the limb

arcuate line of the ilium

smooth ridge located at the inferior margin of the iliac fossa; forms the lateral portion of the pelvic brim

arm

region of the upper limb located between the shoulder and elbow joints; contains the humerus bone

auricular surface of the ilium

roughened area located on the posterior, medial side of the ilium of the hip bone; articulates with the auricular surface of the sacrum to form the sacroiliac joint

base of the metatarsal bone

expanded, proximal end of each metatarsal bone

bicipital groove

intertubercular groove; narrow groove located between the greater and lesser tubercles of the humerus

calcaneus

heel bone; posterior, inferior tarsal bone that forms the heel of the foot

capitate

from the lateral side, the third of the four distal carpal bones; articulates with the scaphoid and lunate proximally, the trapezoid laterally, the hamate medially, and primarily with the third metacarpal distally

capitulum

knob-like bony structure located anteriorly on the lateral, distal end of the humerus

carpal bone

one of the eight small bones that form the wrist and base of the hand; these are grouped as a proximal row consisting of (from lateral to medial) the scaphoid, lunate, triquetrum, and pisiform bones, and a distal row containing (from lateral to medial) the trapezium, trapezoid, capitate, and hamate bones

carpal tunnel

passageway between the anterior forearm and hand formed by the carpal bones and flexor retinaculum

carpometacarpal joint

articulation between one of the carpal bones in the distal row and a metacarpal bone of the hand

clavicle

collarbone; elongated bone that articulates with the manubrium of the sternum medially and the acromion of the scapula laterally

coracoclavicular ligament

strong band of connective tissue that anchors the coracoid process of the scapula to the lateral clavicle; provides important indirect support for the acromioclavicular joint

coracoid process

short, hook-like process that projects anteriorly and laterally from the superior margin of the scapula

coronoid fossa

depression on the anterior surface of the humerus above the trochlea; this space receives the coronoid process of the ulna when the elbow is maximally flexed

coronoid process of the ulna

projecting bony lip located on the anterior, proximal ulna; forms the inferior margin of the trochlear notch

costoclavicular ligament

band of connective tissue that unites the medial clavicle with the first rib

coxal bone

hip bone

cuboid

tarsal bone that articulates posteriorly with the calcaneus bone, medially with the lateral cuneiform bone, and anteriorly with the fourth and fifth metatarsal bones

deltoid tuberosity

roughened, V-shaped region located laterally on the mid-shaft of the humerus

distal radioulnar joint

articulation between the head of the ulna and the ulnar notch of the radius

distal tibiofibular joint

articulation between the distal fibula and the fibular notch of the tibia

elbow joint

joint located between the upper arm and forearm regions of the upper limb; formed by the articulations between the trochlea of the humerus and the trochlear notch of the ulna, and the capitulum of the humerus and the head of the radius

femur

thigh bone; the single bone of the thigh

fibula

thin, non-weight-bearing bone found on the lateral side of the leg

fibular notch

wide groove on the lateral side of the distal tibia for articulation with the fibula at the distal tibiofibular joint

flexor retinaculum

strong band of connective tissue at the anterior wrist that spans the top of the U-shaped grouping of the carpal bones to form the roof of the carpal tunnel

foot

portion of the lower limb located distal to the ankle joint

forearm

region of the upper limb located between the elbow and wrist joints; contains the radius and ulna bones

fossa

(plural = fossae) shallow depression on the surface of a bone

fovea capitis

minor indentation on the head of the femur that serves as the site of attachment for the ligament to the head of the femur

glenohumeral joint

shoulder joint; formed by the articulation between the glenoid cavity of the scapula and the head of the humerus

glenoid cavity

(also, glenoid fossa) shallow depression located on the lateral scapula, between the superior and lateral borders

gluteal tuberosity

roughened area on the posterior side of the proximal femur, extending inferiorly from the base of the greater trochanter

greater pelvis

(also, greater pelvic cavity or false pelvis) broad space above the pelvic brim defined laterally by the fan-like portion of the upper ilium

greater sciatic foramen

pelvic opening formed by the greater sciatic notch of the hip bone, the sacrum, and the sacrospinous ligament

greater sciatic notch

large, U-shaped indentation located on the posterior margin of the ilium, superior to the ischial spine

greater trochanter

large, bony expansion of the femur that projects superiorly from the base of the femoral neck

greater tubercle

enlarged prominence located on the lateral side of the proximal humerus

hallux

big toe; digit 1 of the foot

hamate

from the lateral side, the fourth of the four distal carpal bones; articulates with the lunate and triquetrum proximally, the fourth and fifth metacarpals distally, and the capitate laterally

hand

region of the upper limb distal to the wrist joint

head of the femur

rounded, proximal end of the femur that articulates with the acetabulum of the hip bone to form the hip joint

head of the fibula

small, knob-like, proximal end of the fibula; articulates with the inferior aspect of the lateral condyle of the tibia

head of the humerus

smooth, rounded region on the medial side of the proximal humerus; articulates with the glenoid fossa of the scapula to form the glenohumeral (shoulder) joint

head of the metatarsal bone

expanded, distal end of each metatarsal bone

head of the radius

disc-shaped structure that forms the proximal end of the radius; articulates with the capitulum of the humerus as part of the elbow joint, and with the radial notch of the ulna as part of the proximal radioulnar joint

head of the ulna

small, rounded distal end of the ulna; articulates with the ulnar notch of the distal radius, forming the distal radioulnar joint

hip bone

coxal bone; single bone that forms the pelvic girdle; consists of three areas, the ilium, ischium, and pubis

hip joint

joint located at the proximal end of the lower limb; formed by the articulation between the acetabulum of the hip bone and the head of the femur

hook of the hamate bone

bony extension located on the anterior side of the hamate carpal bone

humerus

single bone of the upper arm

iliac crest

curved, superior margin of the ilium

iliac fossa

shallow depression found on the anterior and medial surfaces of the upper ilium

ilium

superior portion of the hip bone

inferior angle of the scapula

inferior corner of the scapula located where the medial and lateral borders meet

inferior pubic ramus

narrow segment of bone that passes inferiorly and laterally from the pubic body; joins with the ischial ramus to form the ischiopubic ramus

infraglenoid tubercle

small bump or roughened area located on the lateral border of the scapula, near the inferior margin of the glenoid cavity

infraspinous fossa

broad depression located on the posterior scapula, inferior to the spine

intercondylar eminence

irregular elevation on the superior end of the tibia, between the articulating surfaces of the medial and lateral condyles

intercondylar fossa

deep depression on the posterior side of the distal femur that separates the medial and lateral condyles

intermediate cuneiform

middle of the three cuneiform tarsal bones; articulates posteriorly with the navicular bone, medially with the medial cuneiform bone, laterally with the lateral cuneiform bone, and anteriorly with the second metatarsal bone

interosseous border of the fibula

small ridge running down the medial side of the fibular shaft; for attachment of the interosseous membrane between the fibula and tibia

interosseous border of the radius

narrow ridge located on the medial side of the radial shaft; for attachment of the interosseous membrane between the ulna and radius bones

interosseous border of the tibia

small ridge running down the lateral side of the tibial shaft; for attachment of the interosseous membrane between the tibia and fibula

interosseous border of the ulna

narrow ridge located on the lateral side of the ulnar shaft; for attachment of the interosseous membrane between the ulna and radius

interosseous membrane of the forearm

sheet of dense connective tissue that unites the radius and ulna bones

interosseous membrane of the leg

sheet of dense connective tissue that unites the shafts of the tibia and fibula bones

interphalangeal joint

articulation between adjacent phalanx bones of the hand or foot digits

intertrochanteric crest

short, prominent ridge running between the greater and lesser trochanters on the posterior side of the proximal femur

intertrochanteric line

small ridge running between the greater and lesser trochanters on the anterior side of the proximal femur

intertubercular groove (sulcus)

bicipital groove; narrow groove located between the greater and lesser tubercles of the humerus

ischial ramus

bony extension projecting anteriorly and superiorly from the ischial tuberosity; joins with the inferior pubic ramus to form the ischiopubic ramus

ischial spine

pointed, bony projection from the posterior margin of the ischium that separates the greater sciatic notch and lesser sciatic notch

ischial tuberosity

large, roughened protuberance that forms the posteroinferior portion of the hip bone; weight-bearing region of the pelvis when sitting

ischiopubic ramus

narrow extension of bone that connects the ischial tuberosity to the pubic body; formed by the junction of the ischial ramus and inferior pubic ramus

ischium

posteroinferior portion of the hip bone

knee joint

joint that separates the thigh and leg portions of the lower limb; formed by the articulations between the medial and lateral condyles of the femur, and the medial and lateral condyles of the tibia

lateral border of the scapula

diagonally oriented lateral margin of the scapula

lateral condyle of the femur

smooth, articulating surface that forms the distal and posterior sides of the lateral expansion of the distal femur

lateral condyle of the tibia

lateral, expanded region of the proximal tibia that includes the smooth surface that articulates with the lateral condyle of the femur as part of the knee joint

lateral cuneiform

most lateral of the three cuneiform tarsal bones; articulates posteriorly with the navicular bone, medially with the intermediate cuneiform bone, laterally with the cuboid bone, and anteriorly with the third metatarsal bone

lateral epicondyle of the femur

roughened area of the femur located on the lateral side of the lateral condyle

lateral epicondyle of the humerus

small projection located on the lateral side of the distal humerus

lateral malleolus

expanded distal end of the fibula

lateral supracondylar ridge

narrow, bony ridge located along the lateral side of the distal humerus, superior to the lateral epicondyle

leg

portion of the lower limb located between the knee and ankle joints

lesser pelvis

(also, lesser pelvic cavity or true pelvis) narrow space located within the pelvis, defined superiorly by the pelvic brim (pelvic inlet) and inferiorly by the pelvic outlet

lesser sciatic foramen

pelvic opening formed by the lesser sciatic notch of the hip bone, the sacrospinous ligament, and the sacrotuberous ligament

lesser sciatic notch

shallow indentation along the posterior margin of the ischium, inferior to the ischial spine

lesser trochanter

small, bony projection on the medial side of the proximal femur, at the base of the femoral neck

lesser tubercle

small, bony prominence located on anterior side of the proximal humerus

ligament of the head of the femur

ligament that spans the acetabulum of the hip bone and the fovea capitis of the femoral head

limb bud

small elevation that appears on the lateral side of the embryo during the fourth or fifth week of development, which gives rise to an upper or lower limb

linea aspera

longitudinally running bony ridge located in the middle third of the posterior femur

lunate

from the lateral side, the second of the four proximal carpal bones; articulates with the radius proximally, the capitate and hamate distally, the scaphoid laterally, and the triquetrum medially

medial border of the scapula

elongated, medial margin of the scapula

medial condyle of the femur

smooth, articulating surface that forms the distal and posterior sides of the medial expansion of the distal femur

medial condyle of the tibia

medial, expanded region of the proximal tibia that includes the smooth surface that articulates with the medial condyle of the femur as part of the knee joint

medial cuneiform

most medial of the three cuneiform tarsal bones; articulates posteriorly with the navicular bone, laterally with the intermediate cuneiform bone, and anteriorly with the first and second metatarsal bones

medial epicondyle of the femur

roughened area of the distal femur located on the medial side of the medial condyle

medial epicondyle of the humerus

enlarged projection located on the medial side of the distal humerus

medial malleolus

bony expansion located on the medial side of the distal tibia

metacarpal bone

one of the five long bones that form the palm of the hand; numbered 1–5, starting on the lateral (thumb) side of the hand

metacarpophalangeal joint

articulation between the distal end of a metacarpal bone of the hand and a proximal phalanx bone of the thumb or a finger

metatarsal bone

one of the five elongated bones that forms the anterior half of the foot; numbered 1–5, starting on the medial side of the foot

metatarsophalangeal joint

articulation between a metatarsal bone of the foot and the proximal phalanx bone of a toe

midcarpal joint

articulation between the proximal and distal rows of the carpal bones; contributes to movements of the hand at the wrist

navicular

tarsal bone that articulates posteriorly with the talus bone, laterally with the cuboid bone, and anteriorly with the medial, intermediate, and lateral cuneiform bones

neck of the femur

narrowed region located inferior to the head of the femur

neck of the radius

narrowed region immediately distal to the head of the radius

obturator foramen

large opening located in the anterior hip bone, between the pubis and ischium regions

olecranon fossa

large depression located on the posterior side of the distal humerus; this space receives the olecranon process of the ulna when the elbow is fully extended

olecranon process

expanded posterior and superior portions of the proximal ulna; forms the bony tip of the elbow

patella

kneecap; the largest sesamoid bone of the body; articulates with the distal femur

patellar surface

smooth groove located on the anterior side of the distal femur, between the medial and lateral condyles; site of articulation for the patella

pectineal line

narrow ridge located on the superior surface of the superior pubic ramus

pectoral girdle

shoulder girdle; the set of bones, consisting of the scapula and clavicle, which attaches each upper limb to the axial skeleton

pelvic brim

pelvic inlet; the dividing line between the greater and lesser pelvic regions; formed by the superior margin of the pubic symphysis, the pectineal lines of each pubis, the arcuate lines of each ilium, and the sacral promontory

pelvic girdle

hip girdle; consists of a single hip bone, which attaches a lower limb to the sacrum of the axial skeleton

pelvic inlet

pelvic brim

pelvic outlet

inferior opening of the lesser pelvis; formed by the inferior margin of the pubic symphysis, right and left ischiopubic rami and sacrotuberous ligaments, and the tip of the coccyx

pelvis

ring of bone consisting of the right and left hip bones, the sacrum, and the coccyx

phalanx bone of the foot

(plural = phalanges) one of the 14 bones that form the toes; these include the proximal and distal phalanges of the big toe, and the proximal, middle, and distal phalanx bones of toes two through five

phalanx bone of the hand

(plural = phalanges) one of the 14 bones that form the thumb and fingers; these include the proximal and distal phalanges of the thumb, and the proximal, middle, and distal phalanx bones of the fingers two through five

pisiform

from the lateral side, the fourth of the four proximal carpal bones; articulates with the anterior surface of the triquetrum

pollex

(also, thumb) digit 1 of the hand

posterior inferior iliac spine

small, bony projection located at the inferior margin of the auricular surface on the posterior ilium

posterior sacroiliac ligament

strong ligament spanning the sacrum and ilium of the hip bone that supports the posterior side of the sacroiliac joint

posterior superior iliac spine

rounded, posterior end of the iliac crest

proximal radioulnar joint

articulation formed by the radial notch of the ulna and the head of the radius

proximal tibiofibular joint

articulation between the head of the fibula and the inferior aspect of the lateral condyle of the tibia

pubic arch

bony structure formed by the pubic symphysis, and the bodies and inferior pubic rami of the right and left pubic bones

pubic body

enlarged, medial portion of the pubis region of the hip bone

pubic symphysis

joint formed by the articulation between the pubic bodies of the right and left hip bones

pubic tubercle

small bump located on the superior aspect of the pubic body

pubis

anterior portion of the hip bone

radial fossa

small depression located on the anterior humerus above the capitulum; this space receives the head of the radius when the elbow is maximally flexed

radial notch of the ulna

small, smooth area on the lateral side of the proximal ulna; articulates with the head of the radius as part of the proximal radioulnar joint

radial tuberosity

oval-shaped, roughened protuberance located on the medial side of the proximal radius

radiocarpal joint

wrist joint, located between the forearm and hand regions of the upper limb; articulation formed proximally by the distal end of the radius and the fibrocartilaginous pad that unites the distal radius and ulna bone, and distally by the scaphoid, lunate, and triquetrum carpal bones

radius

bone located on the lateral side of the forearm

sacroiliac joint

joint formed by the articulation between the auricular surfaces of the sacrum and ilium

sacrospinous ligament

ligament that spans the sacrum to the ischial spine of the hip bone

sacrotuberous ligament

ligament that spans the sacrum to the ischial tuberosity of the hip bone

scaphoid

from the lateral side, the first of the four proximal carpal bones; articulates with the radius proximally, the trapezoid, trapezium, and capitate distally, and the lunate medially

scapula

shoulder blade bone located on the posterior side of the shoulder

shaft of the femur

cylindrically shaped region that forms the central portion of the femur

shaft of the fibula

elongated, slender portion located between the expanded ends of the fibula

shaft of the humerus

narrow, elongated, central region of the humerus

shaft of the radius

narrow, elongated, central region of the radius

shaft of the tibia

triangular-shaped, central portion of the tibia

shaft of the ulna

narrow, elongated, central region of the ulna

soleal line

small, diagonally running ridge located on the posterior side of the proximal tibia

spine of the scapula

prominent ridge passing mediolaterally across the upper portion of the posterior scapular surface

sternal end of the clavicle

medial end of the clavicle that articulates with the manubrium of the sternum

sternoclavicular joint

articulation between the manubrium of the sternum and the sternal end of the clavicle; forms the only bony attachment between the pectoral girdle of the upper limb and the axial skeleton

styloid process of the radius

pointed projection located on the lateral end of the distal radius

styloid process of the ulna

short, bony projection located on the medial end of the distal ulna

subpubic angle

inverted V-shape formed by the convergence of the right and left ischiopubic rami; this angle is greater than 80 degrees in females and less than 70 degrees in males

subscapular fossa

broad depression located on the anterior (deep) surface of the scapula

superior angle of the scapula

corner of the scapula between the superior and medial borders of the scapula

superior border of the scapula

superior margin of the scapula

superior pubic ramus

narrow segment of bone that passes laterally from the pubic body to join the ilium

supraglenoid tubercle

small bump located at the superior margin of the glenoid cavity

suprascapular notch

small notch located along the superior border of the scapula, medial to the coracoid process

supraspinous fossa

narrow depression located on the posterior scapula, superior to the spine

surgical neck

region of the humerus where the expanded, proximal end joins with the narrower shaft

sustentaculum tali

bony ledge extending from the medial side of the calcaneus bone

talus

tarsal bone that articulates superiorly with the tibia and fibula at the ankle joint; also articulates inferiorly with the calcaneus bone and anteriorly with the navicular bone

tarsal bone

one of the seven bones that make up the posterior foot; includes the calcaneus, talus, navicular, cuboid, medial cuneiform, intermediate cuneiform, and lateral cuneiform bones

thigh

portion of the lower limb located between the hip and knee joints

tibia

shin bone; the large, weight-bearing bone located on the medial side of the leg

tibial tuberosity

elevated area on the anterior surface of the proximal tibia

trapezium

from the lateral side, the first of the four distal carpal bones; articulates with the scaphoid proximally, the first and second metacarpals distally, and the trapezoid medially

trapezoid

from the lateral side, the second of the four distal carpal bones; articulates with the scaphoid proximally, the second metacarpal distally, the trapezium laterally, and the capitate medially

triquetrum

from the lateral side, the third of the four proximal carpal bones; articulates with the lunate laterally, the hamate distally, and has a facet for the pisiform

trochlea

pulley-shaped region located medially at the distal end of the humerus; articulates at the elbow with the trochlear notch of the ulna

trochlear notch

large, C-shaped depression located on the anterior side of the proximal ulna; articulates at the elbow with the trochlea of the humerus

ulna

bone located on the medial side of the forearm

ulnar notch of the radius

shallow, smooth area located on the medial side of the distal radius; articulates with the head of the ulna at the distal radioulnar joint

ulnar tuberosity

roughened area located on the anterior, proximal ulna inferior to the coronoid process

Chapter 9 - Key Terms

abduction

movement in the coronal plane that moves a limb laterally away from the body; spreading of the fingers

acetabular labrum

lip of fibrocartilage that surrounds outer margin of the acetabulum on the hip bone

adduction

movement in the coronal plane that moves a limb medially toward or across the midline of the body; bringing fingers together

amphiarthrosis

slightly mobile joint

annular ligament

intrinsic ligament of the elbow articular capsule that surrounds and supports the head of the radius at the proximal radioulnar joint

anterior cruciate ligament

intracapsular ligament of the knee; extends from anterior, superior surface of the tibia to the inner aspect of the lateral condyle of the femur; resists hyperextension of knee

anterior talofibular ligament

intrinsic ligament located on the lateral side of the ankle joint, between talus bone and lateral malleolus of fibula; supports talus at the talocrural joint and resists excess inversion of the foot

articular capsule

connective tissue structure that encloses the joint cavity of a synovial joint

articular cartilage

thin layer of hyaline cartilage that covers the articulating surfaces of bones at a synovial joint

articular disc

meniscus; a fibrocartilage structure found between the bones of some synovial joints; provides padding or smooths movements between the bones; strongly unites the bones together

articulation

joint of the body

atlanto-occipital joint

articulation between the occipital condyles of the skull and the superior articular processes of the atlas (C1 vertebra)

atlantoaxial joint

series of three articulations between the atlas (C1) vertebra and the axis (C2) vertebra, consisting of the joints between the inferior articular processes of C1 and the superior articular processes of C2, and the articulation between the dens of C2 and the anterior arch of C1

ball-and-socket joint

synovial joint formed between the spherical end of one bone (the ball) that fits into the depression of a second bone (the socket); found at the hip and shoulder joints; functionally classified as a multiaxial joint

biaxial joint

type of diarthrosis; a joint that allows for movements within two planes (two axes)

bursa

connective tissue sac containing lubricating fluid that prevents friction between adjacent structures, such as skin and bone, tendons and bone, or between muscles

calcaneofibular ligament

intrinsic ligament located on the lateral side of the ankle joint, between the calcaneus bone and lateral malleolus of the fibula; supports the talus bone at the ankle joint and resists excess inversion of the foot

cartilaginous joint

joint at which the bones are united by hyaline cartilage (synchondrosis) or fibrocartilage (symphysis)

circumduction

circular motion of the arm, thigh, hand, thumb, or finger that is produced by the sequential combination of flexion, abduction, extension, and adduction

condyloid joint

synovial joint in which the shallow depression at the end of one bone receives a rounded end from a second bone or a rounded structure formed by two bones; found at the metacarpophalangeal joints of the fingers or the radiocarpal joint of the wrist; functionally classified as a biaxial joint

coracohumeral ligament

intrinsic ligament of the shoulder joint; runs from the coracoid process of the scapula to the anterior humerus

deltoid ligament

broad intrinsic ligament located on the medial side of the ankle joint; supports the talus at the talocrural joint and resists excess eversion of the foot

depression

downward (inferior) motion of the scapula or mandible

diarthrosis

freely mobile joint

dorsiflexion

movement at the ankle that brings the top of the foot toward the anterior leg

elbow joint

humeroulnar joint

elevation

upward (superior) motion of the scapula or mandible

eversion

foot movement involving the intertarsal joints of the foot in which the bottom of the foot is turned laterally, away from the midline

extension

movement in the sagittal plane that increases the angle of a joint (straightens the joint); motion involving posterior bending of the vertebral column or returning to the upright position from a flexed position

extrinsic ligament

ligament located outside of the articular capsule of a synovial joint

femoropatellar joint

portion of the knee joint consisting of the articulation between the distal femur and the patella

fibrous joint

joint where the articulating areas of the adjacent bones are connected by fibrous connective tissue

fibular collateral ligament

extrinsic ligament of the knee joint that spans from the lateral epicondyle of the femur to the head of the fibula; resists hyperextension and rotation of the extended knee

flexion

movement in the sagittal plane that decreases the angle of a joint (bends the joint); motion involving anterior bending of the vertebral column

fontanelles

expanded areas of fibrous connective tissue that separate the braincase bones of the skull prior to birth and during the first year after birth

glenohumeral joint

shoulder joint; articulation between the glenoid cavity of the scapula and head of the humerus; multiaxial ball-and-socket joint that allows for flexion/extension, abduction/adduction, circumduction, and medial/lateral rotation of the humerus

glenohumeral ligament

one of the three intrinsic ligaments of the shoulder joint that strengthen the anterior articular capsule

glenoid labrum

lip of fibrocartilage located around the outside margin of the glenoid cavity of the scapula

gomphosis

type of fibrous joint in which the root of a tooth is anchored into its bony jaw socket by strong periodontal ligaments

hinge joint

synovial joint at which the convex surface of one bone articulates with the concave surface of a second bone; includes the elbow, knee, ankle, and interphalangeal joints; functionally classified as a uniaxial joint

humeroradial joint

articulation between the capitulum of the humerus and head of the radius

humeroulnar joint

articulation between the trochlea of humerus and the trochlear notch of the ulna; uniaxial hinge joint that allows for flexion/extension of the forearm

hyperextension

excessive extension of joint, beyond the normal range of movement

hyperflexion

excessive flexion of joint, beyond the normal range of movement

iliofemoral ligament

intrinsic ligament spanning from the ilium of the hip bone to the femur, on the superior-anterior aspect of the hip joint

inferior rotation

movement of the scapula during upper limb adduction in which the glenoid cavity of the scapula moves in a downward direction as the medial end of the scapular spine moves in an upward direction

interosseous membrane

wide sheet of fibrous connective tissue that fills the gap between two parallel bones, forming a syndesmosis; found between the radius and ulna of the forearm and between the tibia and fibula of the leg

intracapsular ligament

ligament that is located within the articular capsule of a synovial joint

intrinsic ligament

ligament that is fused to or incorporated into the wall of the articular capsule of a synovial joint

inversion

foot movement involving the intertarsal joints of the foot in which the bottom of the foot is turned toward the midline

ischiofemoral ligament

intrinsic ligament spanning from the ischium of the hip bone to the femur, on the posterior aspect of the hip joint

joint

site at which two or more bones or bone and cartilage come together (articulate)

joint cavity

space enclosed by the articular capsule of a synovial joint that is filled with synovial fluid and contains the articulating surfaces of the adjacent bones

joint interzone

site within a growing embryonic limb bud that will become a synovial joint

lateral (external) rotation

movement of the arm at the shoulder joint or the thigh at the hip joint that moves the anterior surface of the limb away from the midline of the body

lateral excursion

side-to-side movement of the mandible away from the midline, toward either the right or left side

lateral flexion

bending of the neck or body toward the right or left side

lateral meniscus

C-shaped fibrocartilage articular disc located at the knee, between the lateral condyle of the femur and the lateral condyle of the tibia

lateral tibiofemoral joint

portion of the knee consisting of the articulation between the lateral condyle of the tibia and the lateral condyle of the femur; allows for flexion/extension at the knee

ligament

strong band of dense connective tissue spanning between bones

ligament of the head of the femur

intracapsular ligament that runs from the acetabulum of the hip bone to the head of the femur

medial (internal) rotation

movement of the arm at the shoulder joint or the thigh at the hip joint that brings the anterior surface of the limb toward the midline of the body

medial excursion

side-to-side movement that returns the mandible to the midline

medial meniscus

C-shaped fibrocartilage articular disc located at the knee, between the medial condyle of the femur and medial condyle of the tibia

medial tibiofemoral joint

portion of the knee consisting of the articulation between the medial condyle of the tibia and the medial condyle of the femur; allows for flexion/extension at the knee

meniscus

articular disc

multiaxial joint

type of diarthrosis; a joint that allows for movements within three planes (three axes)

opposition

thumb movement that brings the tip of the thumb in contact with the tip of a finger

patellar ligament

ligament spanning from the patella to the anterior tibia; serves as the final attachment for the quadriceps femoris muscle

periodontal ligament

band of dense connective tissue that anchors the root of a tooth into the bony jaw socket

pivot joint

synovial joint at which the rounded portion of a bone rotates within a ring formed by a ligament and an articulating bone; functionally classified as uniaxial joint

plane joint

synovial joint formed between the flattened articulating surfaces of adjacent bones; functionally classified as a multiaxial joint

plantar flexion

foot movement at the ankle in which the heel is lifted off of the ground

posterior cruciate ligament

intracapsular ligament of the knee; extends from the posterior, superior surface of the tibia to the inner aspect of the medial condyle of the femur; prevents anterior displacement of the femur when the knee is flexed and weight bearing

posterior talofibular ligament

intrinsic ligament located on the lateral side of the ankle joint, between the talus bone and lateral malleolus of the fibula; supports the talus at the talocrural joint and resists excess inversion of the foot

pronated position

forearm position in which the palm faces backward

pronation

forearm motion that moves the palm of the hand from the palm forward to the palm backward position

protraction

anterior motion of the scapula or mandible

proximal radioulnar joint

articulation between head of radius and radial notch of ulna; uniaxial pivot joint that allows for rotation of radius during pronation/supination of forearm

pubofemoral ligament

intrinsic ligament spanning from the pubis of the hip bone to the femur, on the anterior-inferior aspect of the hip joint

radial collateral ligament

intrinsic ligament on the lateral side of the elbow joint; runs from the lateral epicondyle of humerus to merge with the annular ligament

reposition

movement of the thumb from opposition back to the anatomical position (next to index finger)

retraction

posterior motion of the scapula or mandible

rotation

movement of a bone around a central axis (atlantoaxial joint) or around its long axis (proximal radioulnar joint; shoulder or hip joint); twisting of the vertebral column resulting from the summation of small motions between adjacent vertebrae

rotator cuff

strong connective tissue structure formed by the fusion of four rotator cuff muscle tendons to the articular capsule of the shoulder joint; surrounds and supports superior, anterior, lateral, and posterior sides of the humeral head

saddle joint

synovial joint in which the articulating ends of both bones are convex and concave in shape, such as at the first carpometacarpal joint at the base of the thumb; functionally classified as a biaxial joint

subacromial bursa

bursa that protects the supraspinatus muscle tendon and superior end of the humerus from rubbing against the acromion of the scapula

subcutaneous bursa

bursa that prevents friction between skin and an underlying bone

submuscular bursa

bursa that prevents friction between bone and a muscle or between adjacent muscles

subscapular bursa

bursa that prevents rubbing of the subscapularis muscle tendon against the scapula

subtalar joint

articulation between the talus and calcaneus bones of the foot; allows motions that contribute to inversion/eversion of the foot

subtendinous bursa

bursa that prevents friction between bone and a muscle tendon

superior rotation

movement of the scapula during upper limb abduction in which the glenoid cavity of the scapula moves in an upward direction as the medial end of the scapular spine moves in a downward direction

supinated position

forearm position in which the palm faces anteriorly (anatomical position)

supination

forearm motion that moves the palm of the hand from the palm backward to the palm forward position

suture

fibrous joint that connects the bones of the skull (except the mandible); an immobile joint (synarthrosis)

symphysis

type of cartilaginous joint where the bones are joined by fibrocartilage

synarthrosis

immobile or nearly immobile joint

synchondrosis

type of cartilaginous joint where the bones are joined by hyaline cartilage

syndesmosis

type of fibrous joint in which two separated, parallel bones are connected by an interosseous membrane

synostosis

site at which adjacent bones or bony components have fused together

synovial fluid

thick, lubricating fluid that fills the interior of a synovial joint

synovial joint

joint at which the articulating surfaces of the bones are located within a joint cavity formed by an articular capsule

synovial membrane

thin layer that lines the inner surface of the joint cavity at a synovial joint; produces the synovial fluid

talocrural joint

ankle joint; articulation between the talus bone of the foot and medial malleolus of the tibia, distal tibia, and lateral malleolus of the fibula; a uniaxial hinge joint that allows only for dorsiflexion and plantar flexion of the foot

temporomandibular joint (TMJ)

articulation between the condyle of the mandible and the mandibular fossa and articular tubercle of the temporal bone of the skull; allows for depression/elevation (opening/closing of mouth), protraction/retraction, and side-to-side motions of the mandible

tendon

dense connective tissue structure that anchors a muscle to bone

tendon sheath

connective tissue that surrounds a tendon at places where the tendon crosses a joint; contains a lubricating fluid to prevent friction and allow smooth movements of the tendon

tibial collateral ligament

extrinsic ligament of knee joint that spans from the medial epicondyle of the femur to the medial tibia; resists hyperextension and rotation of extended knee

ulnar collateral ligament

intrinsic ligament on the medial side of the elbow joint; spans from the medial epicondyle of the humerus to the medial ulna

uniaxial joint

type of diarthrosis; joint that allows for motion within only one plane (one axis)

zygapophysial joints

facet joints; plane joints between the superior and inferior articular processes of adjacent vertebrae that provide for only limited motions between the vertebrae

Chapter 10 - Key Terms

acetylcholine (ACh)

neurotransmitter that binds at a motor end-plate to trigger depolarization

actin

protein that makes up most of the thin myofilaments in a sarcomere muscle fiber

action potential

change in voltage of a cell membrane in response to a stimulus that results in transmission of an electrical signal; unique to neurons and muscle fibers

aerobic respiration

production of ATP in the presence of oxygen

angiogenesis

formation of blood capillary networks

aponeurosis

broad, tendon-like sheet of connective tissue that attaches a skeletal muscle to another skeletal muscle or to a bone

ATPase

enzyme that hydrolyzes ATP to ADP

atrophy

loss of structural proteins from muscle fibers

autorhythmicity

heart’s ability to control its own contractions

calmodulin

regulatory protein that facilitates contraction in smooth muscles

cardiac muscle

striated muscle found in the heart; joined to one another at intercalated discs and under the regulation of pacemaker cells, which contract as one unit to pump blood through the circulatory system. Cardiac muscle is under involuntary control.

concentric contraction

muscle contraction that shortens the muscle to move a load

contractility

ability to shorten (contract) forcibly

contraction phase

twitch contraction phase when tension increases

creatine phosphate

phosphagen used to store energy from ATP and transfer it to muscle

dense body

sarcoplasmic structure that attaches to the sarcolemma and shortens the muscle as thin filaments slide past thick filaments

depolarize

to reduce the voltage difference between the inside and outside of a cell’s plasma membrane (the sarcolemma for a muscle fiber), making the inside less negative than at rest

desmosome

cell structure that anchors the ends of cardiac muscle fibers to allow contraction to occur

eccentric contraction

muscle contraction that lengthens the muscle as the tension is diminished

elasticity

ability to stretch and rebound

endomysium

loose, and well-hydrated connective tissue covering each muscle fiber in a skeletal muscle

epimysium

outer layer of connective tissue around a skeletal muscle

excitability

ability to undergo neural stimulation

excitation-contraction coupling

sequence of events from motor neuron signaling to a skeletal muscle fiber to contraction of the fiber’s sarcomeres

extensibility

ability to lengthen (extend)

fascicle

bundle of muscle fibers within a skeletal muscle

fast glycolytic (FG)

muscle fiber that primarily uses anaerobic glycolysis

fast oxidative (FO)

intermediate muscle fiber that is between slow oxidative and fast glycolytic fibers

fibrosis

replacement of muscle fibers by scar tissue

glycolysis

anaerobic breakdown of glucose to ATP

graded muscle response

modification of contraction strength

hyperplasia

process in which one cell splits to produce new cells

hypertonia

abnormally high muscle tone

hypertrophy

addition of structural proteins to muscle fibers

hypotonia

abnormally low muscle tone caused by the absence of low-level contractions

intercalated disc

part of the sarcolemma that connects cardiac tissue, and contains gap junctions and desmosomes

isometric contraction

muscle contraction that occurs with no change in muscle length

isotonic contraction

muscle contraction that involves changes in muscle length

lactic acid

product of anaerobic glycolysis

latch-bridges

subset of a cross-bridge in which actin and myosin remain locked together

latent period

the time when a twitch does not produce contraction

motor end-plate

sarcolemma of muscle fiber at the neuromuscular junction, with receptors for the neurotransmitter acetylcholine

motor unit

motor neuron and the group of muscle fibers it innervates

muscle tension

force generated by the contraction of the muscle; tension generated during isotonic contractions and isometric contractions

muscle tone

low levels of muscle contraction that occur when a muscle is not producing movement

myoblast

muscle-forming stem cell

myofibril

long, cylindrical organelle that runs parallel within the muscle fiber and contains the sarcomeres

myogram

instrument used to measure twitch tension

myosin

protein that makes up most of the thick cylindrical myofilament within a sarcomere muscle fiber

myotube

fusion of many myoblast cells

neuromuscular junction (NMJ)

synapse between the axon terminal of a motor neuron and the section of the membrane of a muscle fiber with receptors for the acetylcholine released by the terminal

neurotransmitter

signaling chemical released by nerve terminals that bind to and activate receptors on target cells

oxygen debt

amount of oxygen needed to compensate for ATP produced without oxygen during muscle contraction

pacesetter cell

cell that triggers action potentials in smooth muscle

pericyte

stem cell that regenerates smooth muscle cells

perimysium

connective tissue that bundles skeletal muscle fibers into fascicles within a skeletal muscle

power stroke

action of myosin pulling actin inward (toward the M line)

pyruvic acid

product of glycolysis that can be used in aerobic respiration or converted to lactic acid

recruitment

increase in the number of motor units involved in contraction

relaxation phase

period after twitch contraction when tension decreases

sarcolemma

plasma membrane of a skeletal muscle fiber

sarcomere

longitudinally, repeating functional unit of skeletal muscle, with all of the contractile and associated proteins involved in contraction

sarcopenia

age-related muscle atrophy

sarcoplasm

cytoplasm of a muscle cell

sarcoplasmic reticulum (SR)

specialized smooth endoplasmic reticulum, which stores, releases, and retrieves Ca++

satellite cell

stem cell that helps to repair muscle cells

skeletal muscle

striated, multinucleated muscle that requires signaling from the nervous system to trigger contraction; most skeletal muscles are referred to as voluntary muscles that move bones and produce movement

slow oxidative (SO)

muscle fiber that primarily uses aerobic respiration

smooth muscle

nonstriated, mononucleated muscle in the skin that is associated with hair follicles; assists in moving materials in the walls of internal organs, blood vessels, and internal passageways

somites

blocks of paraxial mesoderm cells

stress-relaxation response

relaxation of smooth muscle tissue after being stretched

synaptic cleft

space between a nerve (axon) terminal and a motor end-plate

T-tubule

projection of the sarcolemma into the interior of the cell

tetanus

a continuous fused contraction

thick filament

the thick myosin strands and their multiple heads projecting from the center of the sarcomere toward, but not all to way to, the Z-discs

thin filament

thin strands of actin and its troponin-tropomyosin complex projecting from the Z-discs toward the center of the sarcomere

treppe

stepwise increase in contraction tension

triad

the grouping of one T-tubule and two terminal cisternae

tropomyosin

regulatory protein that covers myosin-binding sites to prevent actin from binding to myosin

troponin

regulatory protein that binds to actin, tropomyosin, and calcium

twitch

single contraction produced by one action potential

varicosity

enlargement of neurons that release neurotransmitters into synaptic clefts

visceral muscle

smooth muscle found in the walls of visceral organs

voltage-gated sodium channels

membrane proteins that open sodium channels in response to a sufficient voltage change, and initiate and transmit the action potential as Na+ enters through the channel

wave summation

addition of successive neural stimuli to produce greater contraction

Chapter 11 - Key Terms

abduct

move away from midline in the sagittal plane

abductor

moves the bone away from the midline

abductor digiti minimi

muscle that abducts the little finger

abductor pollicis brevis

muscle that abducts the thumb

abductor pollicis longus

muscle that inserts into the first metacarpal

adductor

moves the bone toward the midline

adductor brevis

muscle that adducts and medially rotates the thigh

adductor longus

muscle that adducts, medially rotates, and flexes the thigh

adductor magnus

muscle with an anterior fascicle that adducts, medially rotates and flexes the thigh, and a posterior fascicle that assists in thigh extension

adductor pollicis

muscle that adducts the thumb

agonist

(also, prime mover) muscle whose contraction is responsible for producing a particular motion

anal triangle

posterior triangle of the perineum that includes the anus

anconeus

small muscle on the lateral posterior elbow that extends the forearm

antagonist

muscle that opposes the action of an agonist

anterior compartment of the arm

(anterior flexor compartment of the arm) the biceps brachii, brachialis, brachioradialis, and their associated blood vessels and nerves

anterior compartment of the forearm

(anterior flexor compartment of the forearm) deep and superficial muscles that originate on the humerus and insert into the hand

anterior compartment of the leg

region that includes muscles that dorsiflex the foot

anterior compartment of the thigh

region that includes muscles that flex the thigh and extend the leg

anterior scalene

a muscle anterior to the middle scalene

appendicular

of the arms and legs

axial

of the trunk and head

belly

bulky central body of a muscle

bi

two

biceps brachii

two-headed muscle that crosses the shoulder and elbow joints to flex the forearm while assisting in supinating it and flexing the arm at the shoulder

biceps femoris

hamstring muscle

bipennate

pennate muscle that has fascicles that are located on both sides of the tendon

brachialis

muscle deep to the biceps brachii that provides power in flexing the forearm.

brachioradialis

muscle that can flex the forearm quickly or help lift a load slowly

brevis

short

buccinator

muscle that compresses the cheek

calcaneal tendon

(also, Achilles tendon) strong tendon that inserts into the calcaneal bone of the ankle

caval opening

opening in the diaphragm that allows the inferior vena cava to pass through; foramen for the vena cava

circular

(also, sphincter) fascicles that are concentrically arranged around an opening

compressor urethrae

deep perineal muscle in females

convergent

fascicles that extend over a broad area and converge on a common attachment site

coracobrachialis

muscle that flexes and adducts the arm

corrugator supercilii

prime mover of the eyebrows

deep anterior compartment

flexor pollicis longus, flexor digitorum profundus, and their associated blood vessels and nerves

deep posterior compartment of the forearm

(deep posterior extensor compartment of the forearm) the abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis, and their associated blood vessels and nerves

deep transverse perineal

deep perineal muscle in males

deglutition

swallowing

deltoid

shoulder muscle that abducts the arm as well as flexes and medially rotates it, and extends and laterally rotates it

diaphragm

skeletal muscle that separates the thoracic and abdominal cavities and is dome-shaped at rest

digastric

muscle that has anterior and posterior bellies and elevates the hyoid bone and larynx when one swallows; it also depresses the mandible

dorsal group

region that includes the extensor digitorum brevis

dorsal interossei

muscles that abduct and flex the three middle fingers at the metacarpophalangeal joints and extend them at the interphalangeal joints

epicranial aponeurosis

(also, galea aponeurosis) flat broad tendon that connects the frontalis and occipitalis

erector spinae group

large muscle mass of the back; primary extensor of the vertebral column

extensor

muscle that increases the angle at the joint

extensor carpi radialis brevis

muscle that extends and abducts the hand at the wrist

extensor carpi ulnaris

muscle that extends and adducts the hand

extensor digiti minimi

muscle that extends the little finger

extensor digitorum

muscle that extends the hand at the wrist and the phalanges

extensor digitorum brevis

muscle that extends the toes

extensor digitorum longus

muscle that is lateral to the tibialis anterior

extensor hallucis longus

muscle that is partly deep to the tibialis anterior and extensor digitorum longus

extensor indicis

muscle that inserts onto the tendon of the extensor digitorum of the index finger

extensor pollicis brevis

muscle that inserts onto the base of the proximal phalanx of the thumb

extensor pollicis longus

muscle that inserts onto the base of the distal phalanx of the thumb

extensor radialis longus

muscle that extends and abducts the hand at the wrist

extensor retinaculum

band of connective tissue that extends over the dorsal surface of the hand

external intercostal

superficial intercostal muscles that raise the rib cage

external oblique

superficial abdominal muscle with fascicles that extend inferiorly and medially

extrinsic eye muscles

originate outside the eye and insert onto the outer surface of the white of the eye, and create eyeball movement

extrinsic muscles of the hand

muscles that move the wrists, hands, and fingers and originate on the arm

fascicle

muscle fibers bundled by perimysium into a unit

femoral triangle

region formed at the junction between the hip and the leg and includes the pectineus, femoral nerve, femoral artery, femoral vein, and deep inguinal lymph nodes

fibularis brevis

(also, peroneus brevis) muscle that plantar flexes the foot at the ankle and everts it at the intertarsal joints

fibularis longus

(also, peroneus longus) muscle that plantar flexes the foot at the ankle and everts it at the intertarsal joints

fibularis tertius

small muscle that is associated with the extensor digitorum longus

fixator

synergist that assists an agonist by preventing or reducing movement at another joint, thereby stabilizing the origin of the agonist

flexion

movement that decreases the angle of a joint

flexor

muscle that decreases the angle at the joint

flexor carpi radialis

muscle that flexes and abducts the hand at the wrist

flexor carpi ulnaris

muscle that flexes and adducts the hand at the wrist

flexor digiti minimi brevis

muscle that flexes the little finger

flexor digitorum longus

muscle that flexes the four small toes

flexor digitorum profundus

muscle that flexes the phalanges of the fingers and the hand at the wrist

flexor digitorum superficialis

muscle that flexes the hand and the digits

flexor hallucis longus

muscle that flexes the big toe

flexor pollicis brevis

muscle that flexes the thumb

flexor pollicis longus

muscle that flexes the distal phalanx of the thumb

flexor retinaculum

band of connective tissue that extends over the palmar surface of the hand

frontalis

front part of the occipitofrontalis muscle

fusiform

muscle that has fascicles that are spindle-shaped to create large bellies

gastrocnemius

most superficial muscle of the calf

genioglossus

muscle that originates on the mandible and allows the tongue to move downward and forward

geniohyoid

muscle that depresses the mandible, and raises and pulls the hyoid bone anteriorly

gluteal group

muscle group that extends, flexes, rotates, adducts, and abducts the femur

gluteus maximus

largest of the gluteus muscles that extends the femur

gluteus medius

muscle deep to the gluteus maximus that abducts the femur at the hip

gluteus minimus

smallest of the gluteal muscles and deep to the gluteus medius

gracilis

muscle that adducts the thigh and flexes the leg at the knee

hamstring group

three long muscles on the back of the leg

hyoglossus

muscle that originates on the hyoid bone to move the tongue downward and flatten it

hypothenar

group of muscles on the medial aspect of the palm

hypothenar eminence

rounded contour of muscle at the base of the little finger

iliacus

muscle that, along with the psoas major, makes up the iliopsoas

iliococcygeus

muscle that makes up the levator ani along with the pubococcygeus

iliocostalis cervicis

muscle of the iliocostalis group associated with the cervical region

iliocostalis group

laterally placed muscles of the erector spinae

iliocostalis lumborum

muscle of the iliocostalis group associated with the lumbar region

iliocostalis thoracis

muscle of the iliocostalis group associated with the thoracic region

iliopsoas group

muscle group consisting of iliacus and psoas major muscles, that flexes the thigh at the hip, rotates it laterally, and flexes the trunk of the body onto the hip

iliotibial tract

muscle that inserts onto the tibia; made up of the gluteus maximus and connective tissues of the tensor fasciae latae

inferior extensor retinaculum

cruciate ligament of the ankle

inferior gemellus

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

infrahyoid muscles

anterior neck muscles that are attached to, and inferior to the hyoid bone

infraspinatus

muscle that laterally rotates the arm

innermost intercostal

the deepest intercostal muscles that draw the ribs together

insertion

end of a skeletal muscle that is attached to the structure (usually a bone) that is moved when the muscle contracts

intercostal muscles

muscles that span the spaces between the ribs

intermediate

group of midpalmar muscles

internal intercostal

muscles the intermediate intercostal muscles that draw the ribs together

internal oblique

flat, intermediate abdominal muscle with fascicles that run perpendicular to those of the external oblique

intrinsic muscles of the hand

muscles that move the wrists, hands, and fingers and originate in the palm

ischiococcygeus

muscle that assists the levator ani and pulls the coccyx anteriorly

lateral compartment of the leg

region that includes the fibularis (peroneus) longus and the fibularis (peroneus) brevis and their associated blood vessels and nerves

lateral pterygoid

muscle that moves the mandible from side to side

lateralis

to the outside

latissimus dorsi

broad, triangular axial muscle located on the inferior part of the back

levator ani

pelvic muscle that resists intra-abdominal pressure and supports the pelvic viscera

linea alba

white, fibrous band that runs along the midline of the trunk

longissimus capitis

muscle of the longissimus group associated with the head region

longissimus cervicis

muscle of the longissimus group associated with the cervical region

longissimus group

intermediately placed muscles of the erector spinae

longissimus thoracis

muscle of the longissimus group associated with the thoracic region

longus

long

lumbrical

muscle that flexes each finger at the metacarpophalangeal joints and extend each finger at the interphalangeal joints

masseter

main muscle for chewing that elevates the mandible to close the mouth

mastication

chewing

maximus

largest

medial compartment of the thigh

a region that includes the adductor longus, adductor brevis, adductor magnus, pectineus, gracilis, and their associated blood vessels and nerves

medial pterygoid

muscle that moves the mandible from side to side

medialis

to the inside

medius

medium

middle scalene

longest scalene muscle, located between the anterior and posterior scalenes

minimus

smallest

multifidus

muscle of the lumbar region that helps extend and laterally flex the vertebral column

multipennate

pennate muscle that has a tendon branching within it

mylohyoid

muscle that lifts the hyoid bone and helps press the tongue to the top of the mouth

oblique

at an angle

obturator externus

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

obturator internus

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

occipitalis

posterior part of the occipitofrontalis muscle

occipitofrontalis

muscle that makes up the scalp with a frontal belly and an occipital belly

omohyoid

muscle that has superior and inferior bellies and depresses the hyoid bone

opponens digiti minimi

muscle that brings the little finger across the palm to meet the thumb

opponens pollicis

muscle that moves the thumb across the palm to meet another finger

orbicularis oculi

circular muscle that closes the eye

orbicularis oris

circular muscle that moves the lips

origin

end of a skeletal muscle that is attached to another structure (usually a bone) in a fixed position

palatoglossus

muscle that originates on the soft palate to elevate the back of the tongue

palmar interossei

muscles that abduct and flex each finger at the metacarpophalangeal joints and extend each finger at the interphalangeal joints

palmaris longus

muscle that provides weak flexion of the hand at the wrist

parallel

fascicles that extend in the same direction as the long axis of the muscle

patellar ligament

extension of the quadriceps tendon below the patella

pectineus

muscle that abducts and flexes the femur at the hip

pectoral girdle

shoulder girdle, made up of the clavicle and scapula

pectoralis major

thick, fan-shaped axial muscle that covers much of the superior thorax

pectoralis minor

muscle that moves the scapula and assists in inhalation

pelvic diaphragm

muscular sheet that comprises the levator ani and the ischiococcygeus

pelvic girdle

hips, a foundation for the lower limb

pennate

fascicles that are arranged differently based on their angles to the tendon

perineum

diamond-shaped region between the pubic symphysis, coccyx, and ischial tuberosities

piriformis

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

plantar aponeurosis

muscle that supports the longitudinal arch of the foot

plantar group

four-layered group of intrinsic foot muscles

plantaris

muscle that runs obliquely between the gastrocnemius and the soleus

popliteal fossa

diamond-shaped space at the back of the knee

popliteus

muscle that flexes the leg at the knee and creates the floor of the popliteal fossa

posterior compartment of the leg

region that includes the superficial gastrocnemius, soleus, and plantaris, and the deep popliteus, flexor digitorum longus, flexor hallucis longus, and tibialis posterior

posterior compartment of the thigh

region that includes muscles that flex the leg and extend the thigh

posterior scalene

smallest scalene muscle, located posterior to the middle scalene

prime mover

(also, agonist) principle muscle involved in an action

pronator quadratus

pronator that originates on the ulna and inserts on the radius

pronator teres

pronator that originates on the humerus and inserts on the radius

psoas major

muscle that, along with the iliacus, makes up the iliopsoas

pubococcygeus

muscle that makes up the levator ani along with the iliococcygeus

quadratus femoris

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

quadratus lumborum

posterior part of the abdominal wall that helps with posture and stabilization of the body

quadriceps femoris group

four muscles, that extend and stabilize the knee

quadriceps tendon

(also, patellar tendon) tendon common to all four quadriceps muscles, inserts into the patella

rectus

straight

rectus abdominis

long, linear muscle that extends along the middle of the trunk

rectus femoris

quadricep muscle on the anterior aspect of the thigh

rectus sheaths

tissue that makes up the linea alba

retinacula

fibrous bands that sheath the tendons at the wrist

rhomboid major

muscle that attaches the vertebral border of the scapula to the spinous process of the thoracic vertebrae

rhomboid minor

muscle that attaches the vertebral border of the scapula to the spinous process of the thoracic vertebrae

rotator cuff

(also, musculotendinous cuff) the circle of tendons around the shoulder joint

sartorius

band-like muscle that flexes, abducts, and laterally rotates the leg at the hip

scalene muscles

flex, laterally flex, and rotate the head; contribute to deep inhalation

segmental muscle group

interspinales and intertransversarii muscles that bring together the spinous and transverse processes of each consecutive vertebra

semimembranosus

hamstring muscle

semispinalis capitis

transversospinalis muscle associated with the head region

semispinalis cervicis

transversospinales muscle associated with the cervical region

semispinalis thoracis

transversospinales muscle associated with the thoracic region

semitendinosus

hamstring muscle

serratus anterior

large and flat muscle that originates on the ribs and inserts onto the scapula

soleus

wide, flat muscle deep to the gastrocnemius

sphincter urethrovaginalis

deep perineal muscle in females

spinalis capitis

muscle of the spinalis group associated with the head region

spinalis cervicis

muscle of the spinalis group associated with the cervical region

spinalis group

medially placed muscles of the erector spinae

spinalis thoracis

muscle of the spinalis group associated with the thoracic region

splenius

posterior neck muscles; includes the splenius capitis and splenius cervicis

splenius capitis

neck muscle that inserts into the head region

splenius cervicis

neck muscle that inserts into the cervical region

sternocleidomastoid

major muscle that laterally flexes and rotates the head

sternohyoid

muscle that depresses the hyoid bone

sternothyroid

muscle that depresses the larynx’s thyroid cartilage

styloglossus

muscle that originates on the styloid bone, and allows upward and backward motion of the tongue

stylohyoid

muscle that elevates the hyoid bone posteriorly

subclavius

muscle that stabilizes the clavicle during movement

subscapularis

muscle that originates on the anterior scapula and medially rotates the arm

superficial anterior compartment of the forearm

flexor carpi radialis, palmaris longus, flexor carpi ulnaris, flexor digitorum superficialis, and their associated blood vessels and nerves

superficial posterior compartment of the forearm

extensor radialis longus, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, and their associated blood vessels and nerves

superior extensor retinaculum

transverse ligament of the ankle

superior gemellus

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

supinator

muscle that moves the palm and forearm anteriorly

suprahyoid muscles

neck muscles that are superior to the hyoid bone

supraspinatus

muscle that abducts the arm

synergist

muscle whose contraction helps a prime mover in an action

temporalis

muscle that retracts the mandible

tendinous intersections

three transverse bands of collagen fibers that divide the rectus abdominis into segments

tensor fascia lata

muscle that flexes and abducts the thigh

teres major

muscle that extends the arm and assists in adduction and medial rotation of it

teres minor

muscle that laterally rotates and extends the arm

thenar

group of muscles on the lateral aspect of the palm

thenar eminence

rounded contour of muscle at the base of the thumb

thyrohyoid

muscle that depresses the hyoid bone and elevates the larynx’s thyroid cartilage

tibialis anterior

muscle located on the lateral surface of the tibia

tibialis posterior

muscle that plantar flexes and inverts the foot

transversospinales

muscles that originate at the transverse processes and insert at the spinous processes of the vertebrae

transversus abdominis

deep layer of the abdomen that has fascicles arranged transversely around the abdomen

trapezius

muscle that stabilizes the upper part of the back

tri

three

triceps brachii

three-headed muscle that extends the forearm

unipennate

pennate muscle that has fascicles located on one side of the tendon

urogenital triangle

anterior triangle of the perineum that includes the external genitals

vastus intermedius

quadricep muscle that is between the vastus lateralis and vastus medialis and is deep to the rectus femoris

vastus lateralis

quadricep muscle on the lateral aspect of the thigh

vastus medialis

quadricep muscle on the medial aspect of the thigh

Chapter 12 - Key Terms

absolute refractory period

time during an action period when another action potential cannot be generated because the voltage-gated Na+ channel is inactivated

action potential

change in voltage of a cell membrane in response to a stimulus that results in transmission of an electrical signal; unique to neurons and muscle fibers

activation gate

part of the voltage-gated Na+ channel that opens when the membrane voltage reaches threshold

astrocyte

glial cell type of the CNS that provides support for neurons and maintains the blood-brain barrier

autonomic nervous system (ANS)

functional division of the nervous system that is responsible for homeostatic reflexes that coordinate control of cardiac and smooth muscle, as well as glandular tissue

axon

single process of the neuron that carries an electrical signal (action potential) away from the cell body toward a target cell

axon hillock

tapering of the neuron cell body that gives rise to the axon

axon segment

single stretch of the axon insulated by myelin and bounded by nodes of Ranvier at either end (except for the first, which is after the initial segment, and the last, which is followed by the axon terminal)

axon terminal

end of the axon, where there are usually several branches extending toward the target cell

axoplasm

cytoplasm of an axon, which is different in composition than the cytoplasm of the neuronal cell body

biogenic amine

class of neurotransmitters that are enzymatically derived from amino acids but no longer contain a carboxyl group

bipolar

shape of a neuron with two processes extending from the neuron cell body—the axon and one dendrite

blood-brain barrier (BBB)

physiological barrier between the circulatory system and the central nervous system that establishes a privileged blood supply, restricting the flow of substances into the CNS

brain

the large organ of the central nervous system composed of white and gray matter, contained within the cranium and continuous with the spinal cord

central nervous system (CNS)

anatomical division of the nervous system located within the cranial and vertebral cavities, namely the brain and spinal cord

cerebral cortex

outermost layer of gray matter in the brain, where conscious perception takes place

cerebrospinal fluid (CSF)

circulatory medium within the CNS that is produced by ependymal cells in the choroid plexus filtering the blood

chemical synapse

connection between two neurons, or between a neuron and its target, where a neurotransmitter diffuses across a very short distance

cholinergic system

neurotransmitter system of acetylcholine, which includes its receptors and the enzyme acetylcholinesterase

choroid plexus

specialized structure containing ependymal cells that line blood capillaries and filter blood to produce CSF in the four ventricles of the brain

continuous conduction

slow propagation of an action potential along an unmyelinated axon owing to voltage-gated Na+ channels located along the entire length of the cell membrane

dendrite

one of many branchlike processes that extends from the neuron cell body and functions as a contact for incoming signals (synapses) from other neurons or sensory cells

depolarization

change in a cell membrane potential from rest toward zero

effector protein

enzyme that catalyzes the generation of a new molecule, which acts as the intracellular mediator of the signal that binds to the receptor

electrical synapse

connection between two neurons, or any two electrically active cells, where ions flow directly through channels spanning their adjacent cell membranes

electrochemical exclusion

principle of selectively allowing ions through a channel on the basis of their charge

enteric nervous system (ENS)

neural tissue associated with the digestive system that is responsible for nervous control through autonomic connections

ependymal cell

glial cell type in the CNS responsible for producing cerebrospinal fluid

excitable membrane

cell membrane that regulates the movement of ions so that an electrical signal can be generated

excitatory postsynaptic potential (EPSP)

graded potential in the postsynaptic membrane that is the result of depolarization and makes an action potential more likely to occur

G protein

guanosine triphosphate (GTP) hydrolase that physically moves from the receptor protein to the effector protein to activate the latter

ganglion

localized collection of neuron cell bodies in the peripheral nervous system

gated

property of a channel that determines how it opens under specific conditions, such as voltage change or physical deformation

generator potential

graded potential from dendrites of a unipolar cell which generates the action potential in the initial segment of that cell’s axon

glial cell

one of the various types of neural tissue cells responsible for maintenance of the tissue, and largely responsible for supporting neurons

graded potential

change in the membrane potential that varies in size, depending on the size of the stimulus that elicits it

gray matter

regions of the nervous system containing cell bodies of neurons with few or no myelinated axons; actually may be more pink or tan in color, but called gray in contrast to white matter

inactivation gate

part of a voltage-gated Na+ channel that closes when the membrane potential reaches +30 mV

inhibitory postsynaptic potential (IPSP)

graded potential in the postsynaptic membrane that is the result of hyperpolarization and makes an action potential less likely to occur

initial segment

first part of the axon as it emerges from the axon hillock, where the electrical signals known as action potentials are generated

integration

nervous system function that combines sensory perceptions and higher cognitive functions (memories, learning, emotion, etc.) to produce a response

ionotropic receptor

neurotransmitter receptor that acts as an ion channel gate, and opens by the binding of the neurotransmitter

leakage channel

ion channel that opens randomly and is not gated to a specific event, also known as a non-gated channel

ligand-gated channels

another name for an ionotropic receptor for which a neurotransmitter is the ligand

lower motor neuron

second neuron in the motor command pathway that is directly connected to the skeletal muscle

mechanically gated channel

ion channel that opens when a physical event directly affects the structure of the protein

membrane potential

distribution of charge across the cell membrane, based on the charges of ions

metabotropic receptor

neurotransmitter receptor that involves a complex of proteins that cause metabolic changes in a cell

microglia

glial cell type in the CNS that serves as the resident component of the immune system

multipolar

shape of a neuron that has multiple processes—the axon and two or more dendrites

muscarinic receptor

type of acetylcholine receptor protein that is characterized by also binding to muscarine and is a metabotropic receptor

myelin

lipid-rich insulating substance surrounding the axons of many neurons, allowing for faster transmission of electrical signals

myelin sheath

lipid-rich layer of insulation that surrounds an axon, formed by oligodendrocytes in the CNS and Schwann cells in the PNS; facilitates the transmission of electrical signals

nerve

cord-like bundle of axons located in the peripheral nervous system that transmits sensory input and response output to and from the central nervous system

neuron

neural tissue cell that is primarily responsible for generating and propagating electrical signals into, within, and out of the nervous system

neuropeptide

neurotransmitter type that includes protein molecules and shorter chains of amino acids

neurotransmitter

chemical signal that is released from the synaptic end bulb of a neuron to cause a change in the target cell

nicotinic receptor

type of acetylcholine receptor protein that is characterized by also binding to nicotine and is an ionotropic receptor

node of Ranvier

gap between two myelinated regions of an axon, allowing for strengthening of the electrical signal as it propagates down the axon

nonspecific channel

channel that is not specific to one ion over another, such as a nonspecific cation channel that allows any positively charged ion across the membrane

nucleus

in the nervous system, a localized collection of neuron cell bodies that are functionally related; a “center” of neural function

oligodendrocyte

glial cell type in the CNS that provides the myelin insulation for axons in tracts

peripheral nervous system (PNS)

anatomical division of the nervous system that is largely outside the cranial and vertebral cavities, namely all parts except the brain and spinal cord

postsynaptic potential (PSP)

graded potential in the postsynaptic membrane caused by the binding of neurotransmitter to protein receptors

precentral gyrus of the frontal cortex

region of the cerebral cortex responsible for generating motor commands, where the upper motor neuron cell body is located

process

in cells, an extension of a cell body; in the case of neurons, this includes the axon and dendrites

propagation

movement of an action potential along the length of an axon

receptor potential

graded potential in a specialized sensory cell that directly causes the release of neurotransmitter without an intervening action potential

refractory period

time after the initiation of an action potential when another action potential cannot be generated

relative refractory period

time during the refractory period when a new action potential can only be initiated by a stronger stimulus than the current action potential because voltage-gated K+ channels are not closed

repolarization

return of the membrane potential to its normally negative voltage at the end of the action potential

resistance

property of an axon that relates to the ability of particles to diffuse through the cytoplasm; this is inversely proportional to the fiber diameter

response

nervous system function that causes a target tissue (muscle or gland) to produce an event as a consequence to stimuli

resting membrane potential

the difference in voltage measured across a cell membrane under steady-state conditions, typically -70 mV

saltatory conduction

quick propagation of the action potential along a myelinated axon owing to voltage-gated Na+ channels being present only at the nodes of Ranvier

satellite cell

glial cell type in the PNS that provides support for neurons in the ganglia

Schwann cell

glial cell type in the PNS that provides the myelin insulation for axons in nerves

sensation

nervous system function that receives information from the environment and translates it into the electrical signals of nervous tissue

size exclusion

principle of selectively allowing ions through a channel on the basis of their relative size

soma

in neurons, that portion of the cell that contains the nucleus; the cell body, as opposed to the cell processes (axons and dendrites)

somatic nervous system (SNS)

functional division of the nervous system that is concerned with conscious perception, voluntary movement, and skeletal muscle reflexes

spatial summation

combination of graded potentials across the neuronal cell membrane caused by signals from separate presynaptic elements that add up to initiate an action potential

spinal cord

organ of the central nervous system found within the vertebral cavity and connected with the periphery through spinal nerves; mediates reflex behaviors

stimulus

an event in the external or internal environment that registers as activity in a sensory neuron

summate

to add together, as in the cumulative change in postsynaptic potentials toward reaching threshold in the membrane, either across a span of the membrane or over a certain amount of time

synapse

narrow junction across which a chemical signal passes from neuron to the next, initiating a new electrical signal in the target cell

synaptic cleft

small gap between cells in a chemical synapse where neurotransmitter diffuses from the presynaptic element to the postsynaptic element

synaptic end bulb

swelling at the end of an axon where neurotransmitter molecules are released onto a target cell across a synapse

temporal summation

combination of graded potentials at the same location on a neuron resulting in a strong signal from one input

thalamus

region of the central nervous system that acts as a relay for sensory pathways

thermoreceptor

type of sensory receptor capable of transducing temperature stimuli into neural action potentials

threshold

membrane voltage at which an action potential is initiated

tract

bundle of axons in the central nervous system having the same function and point of origin

unipolar

shape of a neuron which has only one process that includes both the axon and dendrite

upper motor neuron

first neuron in the motor command pathway with its cell body in the cerebral cortex that synapses on the lower motor neuron in the spinal cord

ventricle

central cavity within the brain where CSF is produced and circulates

voltage-gated channel

ion channel that opens because of a change in the charge distributed across the membrane where it is located

white matter

regions of the nervous system containing mostly myelinated axons, making the tissue appear white because of the high lipid content of myelin

Chapter 13 - Key Terms

abducens nerve

sixth cranial nerve; responsible for contraction of one of the extraocular muscles

alar plate

developmental region of the spinal cord that gives rise to the posterior horn of the gray matter

amygdala

nucleus deep in the temporal lobe of the cerebrum that is related to memory and emotional behavior

anterior column

white matter between the anterior horns of the spinal cord composed of many different groups of axons of both ascending and descending tracts

anterior horn

gray matter of the spinal cord containing multipolar motor neurons, sometimes referred to as the ventral horn

anterior median fissure

deep midline feature of the anterior spinal cord, marking the separation between the right and left sides of the cord

anterior spinal artery

blood vessel from the merged branches of the vertebral arteries that runs along the anterior surface of the spinal cord

arachnoid granulation

outpocket of the arachnoid membrane into the dural sinuses that allows for reabsorption of CSF into the blood

arachnoid mater

middle layer of the meninges named for the spider-web–like trabeculae that extend between it and the pia mater

arachnoid trabeculae

filaments between the arachnoid and pia mater within the subarachnoid space

ascending tract

central nervous system fibers carrying sensory information from the spinal cord or periphery to the brain

axillary nerve

systemic nerve of the arm that arises from the brachial plexus

basal forebrain

nuclei of the cerebrum related to modulation of sensory stimuli and attention through broad projections to the cerebral cortex, loss of which is related to Alzheimer’s disease

basal nuclei

nuclei of the cerebrum (with a few components in the upper brain stem and diencephalon) that are responsible for assessing cortical movement commands and comparing them with the general state of the individual through broad modulatory activity of dopamine neurons; largely related to motor functions, as evidenced through the symptoms of Parkinson’s and Huntington’s diseases

basal plate

developmental region of the spinal cord that gives rise to the lateral and anterior horns of gray matter

basilar artery

blood vessel from the merged vertebral arteries that runs along the dorsal surface of the brain stem

brachial plexus

nerve plexus associated with the lower cervical spinal nerves and first thoracic spinal nerve

brain stem

region of the adult brain that includes the midbrain, pons, and medulla oblongata and develops from the mesencephalon, metencephalon, and myelencephalon of the embryonic brain

Broca’s area

region of the frontal lobe associated with the motor commands necessary for speech production and located only in the cerebral hemisphere responsible for language production, which is the left side in approximately 95 percent of the population

Brodmann’s areas

mapping of regions of the cerebral cortex based on microscopic anatomy that relates specific areas to functional differences, as described by Brodmann in the early 1900s

carotid canal

opening in the temporal bone through which the internal carotid artery enters the cranium

cauda equina

bundle of spinal nerve roots that descend from the lower spinal cord below the first lumbar vertebra and lie within the vertebral cavity; has the appearance of a horse's tail

caudate

nucleus deep in the cerebrum that is part of the basal nuclei; along with the putamen, it is part of the striatum

central canal

hollow space within the spinal cord that is the remnant of the center of the neural tube

central sulcus

surface landmark of the cerebral cortex that marks the boundary between the frontal and parietal lobes

cephalic flexure

curve in midbrain of the embryo that positions the forebrain ventrally

cerebellum

region of the adult brain connected primarily to the pons that developed from the metencephalon (along with the pons) and is largely responsible for comparing information from the cerebrum with sensory feedback from the periphery through the spinal cord

cerebral aqueduct

connection of the ventricular system between the third and fourth ventricles located in the midbrain

cerebral cortex

outer gray matter covering the forebrain, marked by wrinkles and folds known as gyri and sulci

cerebral hemisphere

one half of the bilaterally symmetrical cerebrum

cerebrum

region of the adult brain that develops from the telencephalon and is responsible for higher neurological functions such as memory, emotion, and consciousness

cervical plexus

nerve plexus associated with the upper cervical spinal nerves

choroid plexus

specialized structures containing ependymal cells lining blood capillaries that filter blood to produce CSF in the four ventricles of the brain

circle of Willis

unique anatomical arrangement of blood vessels around the base of the brain that maintains perfusion of blood into the brain even if one component of the structure is blocked or narrowed

common carotid artery

blood vessel that branches off the aorta (or the brachiocephalic artery on the right) and supplies blood to the head and neck

corpus callosum

large white matter structure that connects the right and left cerebral hemispheres

cranial nerve

one of twelve nerves connected to the brain that are responsible for sensory or motor functions of the head and neck

cranial nerve ganglion

sensory ganglion of cranial nerves

descending tract

central nervous system fibers carrying motor commands from the brain to the spinal cord or periphery

diencephalon

region of the adult brain that retains its name from embryonic development and includes the thalamus and hypothalamus

direct pathway

connections within the basal nuclei from the striatum to the globus pallidus internal segment and substantia nigra pars reticulata that disinhibit the thalamus to increase cortical control of movement

disinhibition

disynaptic connection in which the first synapse inhibits the second cell, which then stops inhibiting the final target

dorsal (posterior) nerve root

axons entering the posterior horn of the spinal cord

dorsal (posterior) root ganglion

sensory ganglion attached to the posterior nerve root of a spinal nerve

dura mater

tough, fibrous, outer layer of the meninges that is attached to the inner surface of the cranium and vertebral column and surrounds the entire CNS

dural sinus

any of the venous structures surrounding the brain, enclosed within the dura mater, which drain blood from the CNS to the common venous return of the jugular veins

endoneurium

innermost layer of connective tissue that surrounds individual axons within a nerve

enteric nervous system

peripheral structures, namely ganglia and nerves, that are incorporated into the digestive system organs

enteric plexus

neuronal plexus in the wall of the intestines, which is part of the enteric nervous system

epineurium

outermost layer of connective tissue that surrounds an entire nerve

epithalamus

region of the diecephalon containing the pineal gland

esophageal plexus

neuronal plexus in the wall of the esophagus that is part of the enteric nervous system

extraocular muscles

six skeletal muscles that control eye movement within the orbit

facial nerve

seventh cranial nerve; responsible for contraction of the facial muscles and for part of the sense of taste, as well as causing saliva production

fascicle

small bundles of nerve or muscle fibers enclosed by connective tissue

femoral nerve

systemic nerve of the anterior leg that arises from the lumbar plexus

fibular nerve

systemic nerve of the posterior leg that begins as part of the sciatic nerve

foramen magnum

large opening in the occipital bone of the skull through which the spinal cord emerges and the vertebral arteries enter the cranium

forebrain

anterior region of the adult brain that develops from the prosencephalon and includes the cerebrum and diencephalon

fourth ventricle

the portion of the ventricular system that is in the region of the brain stem and opens into the subarachnoid space through the median and lateral apertures

frontal eye field

region of the frontal lobe associated with motor commands to orient the eyes toward an object of visual attention

frontal lobe

region of the cerebral cortex directly beneath the frontal bone of the cranium

gastric plexuses

neuronal networks in the wall of the stomach that are part of the enteric nervous system

globus pallidus

nuclei deep in the cerebrum that are part of the basal nuclei and can be divided into the internal and external segments

glossopharyngeal nerve

ninth cranial nerve; responsible for contraction of muscles in the tongue and throat and for part of the sense of taste, as well as causing saliva production

gyrus

ridge formed by convolutions on the surface of the cerebrum or cerebellum

hindbrain

posterior region of the adult brain that develops from the rhombencephalon and includes the pons, medulla oblongata, and cerebellum

hippocampus

gray matter deep in the temporal lobe that is very important for long-term memory formation

hypoglossal nerve

twelfth cranial nerve; responsible for contraction of muscles of the tongue

hypothalamus

major region of the diencephalon that is responsible for coordinating autonomic and endocrine control of homeostasis

indirect pathway

connections within the basal nuclei from the striatum through the globus pallidus external segment and subthalamic nucleus to the globus pallidus internal segment/substantia nigra pars compacta that result in inhibition of the thalamus to decrease cortical control of movement

inferior colliculus

half of the midbrain tectum that is part of the brain stem auditory pathway

inferior olive

nucleus in the medulla that is involved in processing information related to motor control

intercostal nerve

systemic nerve in the thoracic cavity that is found between two ribs

internal carotid artery

branch from the common carotid artery that enters the cranium and supplies blood to the brain

interventricular foramina

openings between the lateral ventricles and third ventricle allowing for the passage of CSF

jugular veins

blood vessels that return “used” blood from the head and neck

kinesthesia

general sensory perception of movement of the body

lateral apertures

pair of openings from the fourth ventricle to the subarachnoid space on either side and between the medulla and cerebellum

lateral column

white matter of the spinal cord between the posterior horn on one side and the axons from the anterior horn on the same side; composed of many different groups of axons, of both ascending and descending tracts, carrying motor commands to and from the brain

lateral horn

region of the spinal cord gray matter in the thoracic, upper lumbar, and sacral regions that is the central component of the sympathetic division of the autonomic nervous system

lateral sulcus

surface landmark of the cerebral cortex that marks the boundary between the temporal lobe and the frontal and parietal lobes

lateral ventricles

portions of the ventricular system that are in the region of the cerebrum

limbic cortex

collection of structures of the cerebral cortex that are involved in emotion, memory, and behavior and are part of the larger limbic system

limbic system

structures at the edge (limit) of the boundary between the forebrain and hindbrain that are most associated with emotional behavior and memory formation

longitudinal fissure

large separation along the midline between the two cerebral hemispheres

lumbar plexus

nerve plexus associated with the lumbar spinal nerves

lumbar puncture

procedure used to withdraw CSF from the lower lumbar region of the vertebral column that avoids the risk of damaging CNS tissue because the spinal cord ends at the upper lumbar vertebrae

median aperture

singular opening from the fourth ventricle into the subarachnoid space at the midline between the medulla and cerebellum

median nerve

systemic nerve of the arm, located between the ulnar and radial nerves

meninges

protective outer coverings of the CNS composed of connective tissue

mesencephalon

primary vesicle of the embryonic brain that does not significantly change through the rest of embryonic development and becomes the midbrain

metencephalon

secondary vesicle of the embryonic brain that develops into the pons and the cerebellum

midbrain

middle region of the adult brain that develops from the mesencephalon

myelencephalon

secondary vesicle of the embryonic brain that develops into the medulla

nerve plexus

network of nerves without neuronal cell bodies included

neural crest

tissue that detaches from the edges of the neural groove and migrates through the embryo to develop into peripheral structures of both nervous and non-nervous tissues

neural fold

elevated edge of the neural groove

neural groove

region of the neural plate that folds into the dorsal surface of the embryo and closes off to become the neural tube

neural plate

thickened layer of neuroepithelium that runs longitudinally along the dorsal surface of an embryo and gives rise to nervous system tissue

neural tube

precursor to structures of the central nervous system, formed by the invagination and separation of neuroepithelium

neuraxis

central axis to the nervous system, from the posterior to anterior ends of the neural tube; the inferior tip of the spinal cord to the anterior surface of the cerebrum

occipital lobe

region of the cerebral cortex directly beneath the occipital bone of the cranium

occipital sinuses

dural sinuses along the edge of the occipital lobes of the cerebrum

oculomotor nerve

third cranial nerve; responsible for contraction of four of the extraocular muscles, the muscle in the upper eyelid, and pupillary constriction

olfaction

special sense responsible for smell, which has a unique, direct connection to the cerebrum

olfactory nerve

first cranial nerve; responsible for the sense of smell

optic nerve

second cranial nerve; responsible for visual sensation

orthostatic reflex

sympathetic function that maintains blood pressure when standing to offset the increased effect of gravity

paravertebral ganglia

autonomic ganglia superior to the sympathetic chain ganglia

parietal lobe

region of the cerebral cortex directly beneath the parietal bone of the cranium

parieto-occipital sulcus

groove in the cerebral cortex representing the border between the parietal and occipital cortices

perineurium

layer of connective tissue surrounding fascicles within a nerve

phrenic nerve

systemic nerve from the cervical plexus that innervates the diaphragm

pia mater

thin, innermost membrane of the meninges that directly covers the surface of the CNS

plexus

network of nerves or nervous tissue

postcentral gyrus

primary motor cortex located in the frontal lobe of the cerebral cortex

posterior columns

white matter of the spinal cord that lies between the posterior horns of the gray matter, sometimes referred to as the dorsal column; composed of axons of ascending tracts that carry sensory information up to the brain

posterior horn

gray matter region of the spinal cord in which sensory input arrives, sometimes referred to as the dorsal horn

posterior median sulcus

midline feature of the posterior spinal cord, marking the separation between right and left sides of the cord

posterolateral sulcus

feature of the posterior spinal cord marking the entry of posterior nerve roots and the separation between the posterior and lateral columns of the white matter

precentral gyrus

ridge just posterior to the central sulcus, in the parietal lobe, where somatosensory processing initially takes place in the cerebrum

prefrontal lobe

specific region of the frontal lobe anterior to the more specific motor function areas, which can be related to the early planning of movements and intentions to the point of being personality-type functions

premotor area

region of the frontal lobe responsible for planning movements that will be executed through the primary motor cortex

prevertebral ganglia

autonomic ganglia that are anterior to the vertebral column and functionally related to the sympathetic chain ganglia

primary vesicle

initial enlargements of the anterior neural tube during embryonic development that develop into the forebrain, midbrain, and hindbrain

proprioception

general sensory perceptions providing information about location and movement of body parts; the “sense of the self”

prosencephalon

primary vesicle of the embryonic brain that develops into the forebrain, which includes the cerebrum and diencephalon

putamen

nucleus deep in the cerebrum that is part of the basal nuclei; along with the caudate, it is part of the striatum

radial nerve

systemic nerve of the arm, the distal component of which is located near the radial bone

reticular formation

diffuse region of gray matter throughout the brain stem that regulates sleep, wakefulness, and states of consciousness

rhombencephalon

primary vesicle of the embryonic brain that develops into the hindbrain, which includes the pons, cerebellum, and medulla

sacral plexus

nerve plexus associated with the lower lumbar and sacral spinal nerves

saphenous nerve

systemic nerve of the lower anterior leg that is a branch from the femoral nerve

sciatic nerve

systemic nerve from the sacral plexus that is a combination of the tibial and fibular nerves and extends across the hip joint and gluteal region into the upper posterior leg

sciatica

painful condition resulting from inflammation or compression of the sciatic nerve or any of the spinal nerves that contribute to it

secondary vesicle

five vesicles that develop from primary vesicles, continuing the process of differentiation of the embryonic brain

sigmoid sinuses

dural sinuses that drain directly into the jugular veins

somatosensation

general senses related to the body, usually thought of as the senses of touch, which would include pain, temperature, and proprioception

spinal accessory nerve

eleventh cranial nerve; responsible for contraction of neck muscles

spinal nerve

one of 31 nerves connected to the spinal cord

straight sinus

dural sinus that drains blood from the deep center of the brain to collect with the other sinuses

striatum

the caudate and putamen collectively, as part of the basal nuclei, which receive input from the cerebral cortex

subarachnoid space

space between the arachnoid mater and pia mater that contains CSF and the fibrous connections of the arachnoid trabeculae

subcortical nucleus

all the nuclei beneath the cerebral cortex, including the basal nuclei and the basal forebrain

substantia nigra pars compacta

nuclei within the basal nuclei that release dopamine to modulate the function of the striatum; part of the motor pathway

substantia nigra pars reticulata

nuclei within the basal nuclei that serve as an output center of the nuclei; part of the motor pathway

subthalamus

nucleus within the basal nuclei that is part of the indirect pathway

sulcus

groove formed by convolutions in the surface of the cerebral cortex

superior colliculus

half of the midbrain tectum that is responsible for aligning visual, auditory, and somatosensory spatial perceptions

superior sagittal sinus

dural sinus that runs along the top of the longitudinal fissure and drains blood from the majority of the outer cerebrum

sympathetic chain ganglia

autonomic ganglia in a chain along the anterolateral aspect of the vertebral column that are responsible for contributing to homeostatic mechanisms of the autonomic nervous system

systemic nerve

nerve in the periphery distal to a nerve plexus or spinal nerve

tectum

region of the midbrain, thought of as the roof of the cerebral aqueduct, which is subdivided into the inferior and superior colliculi

tegmentum

region of the midbrain, thought of as the floor of the cerebral aqueduct, which continues into the pons and medulla as the floor of the fourth ventricle

telencephalon

secondary vesicle of the embryonic brain that develops into the cerebrum

temporal lobe

region of the cerebral cortex directly beneath the temporal bone of the cranium

terminal ganglion

autonomic ganglia that are near or within the walls of organs that are responsible for contributing to homeostatic mechanisms of the autonomic nervous system

thalamus

major region of the diencephalon that is responsible for relaying information between the cerebrum and the hindbrain, spinal cord, and periphery

third ventricle

portion of the ventricular system that is in the region of the diencephalon

tibial nerve

systemic nerve of the posterior leg that begins as part of the sciatic nerve

transverse sinuses

dural sinuses that drain along either side of the occipital–cerebellar space

trigeminal ganglion

sensory ganglion that contributes sensory fibers to the trigeminal nerve

trigeminal nerve

fifth cranial nerve; responsible for cutaneous sensation of the face and contraction of the muscles of mastication

trochlear nerve

fourth cranial nerve; responsible for contraction of one of the extraocular muscles

ulnar nerve

systemic nerve of the arm located close to the ulna, a bone of the forearm

vagus nerve

tenth cranial nerve; responsible for the autonomic control of organs in the thoracic and upper abdominal cavities

ventral (anterior) nerve root

axons emerging from the anterior or lateral horns of the spinal cord

ventricles

remnants of the hollow center of the neural tube that are spaces for cerebrospinal fluid to circulate through the brain

vertebral arteries

arteries that ascend along either side of the vertebral column through the transverse foramina of the cervical vertebrae and enter the cranium through the foramen magnum

vestibulocochlear nerve

eighth cranial nerve; responsible for the sensations of hearing and balance

Chapter 14 - Key Terms

alkaloid

substance, usually from a plant source, that is chemically basic with respect to pH and will stimulate bitter receptors

amacrine cell

type of cell in the retina that connects to the bipolar cells near the outer synaptic layer and provides the basis for early image processing within the retina

ampulla

in the ear, the structure at the base of a semicircular canal that contains the hair cells and cupula for transduction of rotational movement of the head

anosmia

loss of the sense of smell; usually the result of physical disruption of the first cranial nerve

anterior corticospinal tract

division of the corticospinal pathway that travels through the ventral (anterior) column of the spinal cord and controls axial musculature through the medial motor neurons in the ventral (anterior) horn

aqueous humor

watery fluid that fills the anterior chamber containing the cornea, iris, ciliary body, and lens of the eye

ascending pathway

fiber structure that relays sensory information from the periphery through the spinal cord and brain stem to other structures of the brain

association area

region of cortex connected to a primary sensory cortical area that further processes the information to generate more complex sensory perceptions

audition

sense of hearing

auricle

fleshy external structure of the ear

basilar membrane

in the ear, the floor of the cochlear duct on which the organ of Corti sits

Betz cells

output cells of the primary motor cortex that cause musculature to move through synapses on cranial and spinal motor neurons

binocular depth cues

indications of the distance of visual stimuli on the basis of slight differences in the images projected onto either retina

bipolar cell

cell type in the retina that connects the photoreceptors to the RGCs

Broca’s area

region of the frontal lobe associated with the motor commands necessary for speech production

capsaicin

molecule that activates nociceptors by interacting with a temperature-sensitive ion channel and is the basis for “hot” sensations in spicy food

cerebral peduncles

segments of the descending motor pathway that make up the white matter of the ventral midbrain

cervical enlargement

region of the ventral (anterior) horn of the spinal cord that has a larger population of motor neurons for the greater number of and finer control of muscles of the upper limb

chemoreceptor

sensory receptor cell that is sensitive to chemical stimuli, such as in taste, smell, or pain

chief sensory nucleus

component of the trigeminal nuclei that is found in the pons

choroid

highly vascular tissue in the wall of the eye that supplies the outer retina with blood

ciliary body

smooth muscle structure on the interior surface of the iris that controls the shape of the lens through the zonule fibers

circadian rhythm

internal perception of the daily cycle of light and dark based on retinal activity related to sunlight

cochlea

auditory portion of the inner ear containing structures to transduce sound stimuli

cochlear duct

space within the auditory portion of the inner ear that contains the organ of Corti and is adjacent to the scala tympani and scala vestibuli on either side

cone photoreceptor

one of the two types of retinal receptor cell that is specialized for color vision through the use of three photopigments distributed through three separate populations of cells

contralateral

word meaning “on the opposite side,” as in axons that cross the midline in a fiber tract

cornea

fibrous covering of the anterior region of the eye that is transparent so that light can pass through it

corneal reflex

protective response to stimulation of the cornea causing contraction of the orbicularis oculi muscle resulting in blinking of the eye

corticobulbar tract

connection between the cortex and the brain stem responsible for generating movement

corticospinal tract

connection between the cortex and the spinal cord responsible for generating movement

cupula

specialized structure within the base of a semicircular canal that bends the stereocilia of hair cells when the head rotates by way of the relative movement of the enclosed fluid

decussate

to cross the midline, as in fibers that project from one side of the body to the other

dorsal column system

ascending tract of the spinal cord associated with fine touch and proprioceptive sensations

dorsal stream

connections between cortical areas from the occipital to parietal lobes that are responsible for the perception of visual motion and guiding movement of the body in relation to that motion

encapsulated ending

configuration of a sensory receptor neuron with dendrites surrounded by specialized structures to aid in transduction of a particular type of sensation, such as the lamellated corpuscles in the deep dermis and subcutaneous tissue

equilibrium

sense of balance that includes sensations of position and movement of the head

executive functions

cognitive processes of the prefrontal cortex that lead to directing goal-directed behavior, which is a precursor to executing motor commands

external ear

structures on the lateral surface of the head, including the auricle and the ear canal back to the tympanic membrane

exteroceptor

sensory receptor that is positioned to interpret stimuli from the external environment, such as photoreceptors in the eye or somatosensory receptors in the skin

extraocular muscle

one of six muscles originating out of the bones of the orbit and inserting into the surface of the eye which are responsible for moving the eye

extrapyramidal system

pathways between the brain and spinal cord that are separate from the corticospinal tract and are responsible for modulating the movements generated through that primary pathway

fasciculus cuneatus

lateral division of the dorsal column system composed of fibers from sensory neurons in the upper body

fasciculus gracilis

medial division of the dorsal column system composed of fibers from sensory neurons in the lower body

fibrous tunic

outer layer of the eye primarily composed of connective tissue known as the sclera and cornea

fovea

exact center of the retina at which visual stimuli are focused for maximal acuity, where the retina is thinnest, at which there is nothing but photoreceptors

free nerve ending

configuration of a sensory receptor neuron with dendrites in the connective tissue of the organ, such as in the dermis of the skin, that are most often sensitive to chemical, thermal, and mechanical stimuli

frontal eye fields

area of the prefrontal cortex responsible for moving the eyes to attend to visual stimuli

general sense

any sensory system that is distributed throughout the body and incorporated into organs of multiple other systems, such as the walls of the digestive organs or the skin

gustation

sense of taste

gustatory receptor cells

sensory cells in the taste bud that transduce the chemical stimuli of gustation

hair cells

mechanoreceptor cells found in the inner ear that transduce stimuli for the senses of hearing and balance

incus

(also, anvil) ossicle of the middle ear that connects the malleus to the stapes

inferior colliculus

last structure in the auditory brainstem pathway that projects to the thalamus and superior colliculus

inferior oblique

extraocular muscle responsible for lateral rotation of the eye

inferior rectus

extraocular muscle responsible for looking down

inner ear

structure within the temporal bone that contains the sensory apparati of hearing and balance

inner segment

in the eye, the section of a photoreceptor that contains the nucleus and other major organelles for normal cellular functions

inner synaptic layer

layer in the retina where bipolar cells connect to RGCs

interaural intensity difference

cue used to aid sound localization in the horizontal plane that compares the relative loudness of sounds at the two ears, because the ear closer to the sound source will hear a slightly more intense sound

interaural time difference

cue used to help with sound localization in the horizontal plane that compares the relative time of arrival of sounds at the two ears, because the ear closer to the sound source will receive the stimulus microseconds before the other ear

internal capsule

segment of the descending motor pathway that passes between the caudate nucleus and the putamen

interoceptor

sensory receptor that is positioned to interpret stimuli from internal organs, such as stretch receptors in the wall of blood vessels

ipsilateral

word meaning on the same side, as in axons that do not cross the midline in a fiber tract

iris

colored portion of the anterior eye that surrounds the pupil

kinesthesia

sense of body movement based on sensations in skeletal muscles, tendons, joints, and the skin

lacrimal duct

duct in the medial corner of the orbit that drains tears into the nasal cavity

lacrimal gland

gland lateral to the orbit that produces tears to wash across the surface of the eye

lateral corticospinal tract

division of the corticospinal pathway that travels through the lateral column of the spinal cord and controls appendicular musculature through the lateral motor neurons in the ventral (anterior) horn

lateral geniculate nucleus

thalamic target of the RGCs that projects to the visual cortex

lateral rectus

extraocular muscle responsible for abduction of the eye

lens

component of the eye that focuses light on the retina

levator palpebrae superioris

muscle that causes elevation of the upper eyelid, controlled by fibers in the oculomotor nerve

lumbar enlargement

region of the ventral (anterior) horn of the spinal cord that has a larger population of motor neurons for the greater number of muscles of the lower limb

macula

enlargement at the base of a semicircular canal at which transduction of equilibrium stimuli takes place within the ampulla

malleus

(also, hammer) ossicle that is directly attached to the tympanic membrane

mechanoreceptor

receptor cell that transduces mechanical stimuli into an electrochemical signal

medial geniculate nucleus

thalamic target of the auditory brain stem that projects to the auditory cortex

medial lemniscus

fiber tract of the dorsal column system that extends from the nuclei gracilis and cuneatus to the thalamus, and decussates

medial rectus

extraocular muscle responsible for adduction of the eye

mesencephalic nucleus

component of the trigeminal nuclei that is found in the midbrain

middle ear

space within the temporal bone between the ear canal and bony labyrinth where the ossicles amplify sound waves from the tympanic membrane to the oval window

multimodal integration area

region of the cerebral cortex in which information from more than one sensory modality is processed to arrive at higher level cortical functions such as memory, learning, or cognition

neural tunic

layer of the eye that contains nervous tissue, namely the retina

nociceptor

receptor cell that senses pain stimuli

nucleus cuneatus

medullary nucleus at which first-order neurons of the dorsal column system synapse specifically from the upper body and arms

nucleus gracilis

medullary nucleus at which first-order neurons of the dorsal column system synapse specifically from the lower body and legs

odorant molecules

volatile chemicals that bind to receptor proteins in olfactory neurons to stimulate the sense of smell

olfaction

sense of smell

olfactory bulb

central target of the first cranial nerve; located on the ventral surface of the frontal lobe in the cerebrum

olfactory epithelium

region of the nasal epithelium where olfactory neurons are located

olfactory sensory neuron

receptor cell of the olfactory system, sensitive to the chemical stimuli of smell, the axons of which compose the first cranial nerve

opsin

protein that contains the photosensitive cofactor retinal for phototransduction

optic chiasm

decussation point in the visual system at which medial retina fibers cross to the other side of the brain

optic disc

spot on the retina at which RGC axons leave the eye and blood vessels of the inner retina pass

optic nerve

second cranial nerve, which is responsible visual sensation

optic tract

name for the fiber structure containing axons from the retina posterior to the optic chiasm representing their CNS location

organ of Corti

structure in the cochlea in which hair cells transduce movements from sound waves into electrochemical signals

osmoreceptor

receptor cell that senses differences in the concentrations of bodily fluids on the basis of osmotic pressure

ossicles

three small bones in the middle ear

otolith

layer of calcium carbonate crystals located on top of the otolithic membrane

otolithic membrane

gelatinous substance in the utricle and saccule of the inner ear that contains calcium carbonate crystals and into which the stereocilia of hair cells are embedded

outer segment

in the eye, the section of a photoreceptor that contains opsin molecules that transduce light stimuli

outer synaptic layer

layer in the retina at which photoreceptors connect to bipolar cells

oval window

membrane at the base of the cochlea where the stapes attaches, marking the beginning of the scala vestibuli

palpebral conjunctiva

membrane attached to the inner surface of the eyelids that covers the anterior surface of the cornea

papilla

for gustation, a bump-like projection on the surface of the tongue that contains taste buds

photoisomerization

chemical change in the retinal molecule that alters the bonding so that it switches from the 11-cis-retinal isomer to the all-trans-retinal isomer

photon

individual “packet” of light

photoreceptor

receptor cell specialized to respond to light stimuli

premotor cortex

cortical area anterior to the primary motor cortex that is responsible for planning movements

primary sensory cortex

region of the cerebral cortex that initially receives sensory input from an ascending pathway from the thalamus and begins the processing that will result in conscious perception of that modality

proprioception

sense of position and movement of the body

proprioceptor

receptor cell that senses changes in the position and kinesthetic aspects of the body

pupil

open hole at the center of the iris that light passes through into the eye

pyramidal decussation

location at which corticospinal tract fibers cross the midline and segregate into the anterior and lateral divisions of the pathway

pyramids

segment of the descending motor pathway that travels in the anterior position of the medulla

receptor cell

cell that transduces environmental stimuli into neural signals

red nucleus

midbrain nucleus that sends corrective commands to the spinal cord along the rubrospinal tract, based on disparity between an original command and the sensory feedback from movement

reticulospinal tract

extrapyramidal connections between the brain stem and spinal cord that modulate movement, contribute to posture, and regulate muscle tone

retina

nervous tissue of the eye at which phototransduction takes place

retinal

cofactor in an opsin molecule that undergoes a biochemical change when struck by a photon (pronounced with a stress on the last syllable)

retinal ganglion cell (RGC)

neuron of the retina that projects along the second cranial nerve

rhodopsin

photopigment molecule found in the rod photoreceptors

rod photoreceptor

one of the two types of retinal receptor cell that is specialized for low-light vision

round window

membrane that marks the end of the scala tympani

rubrospinal tract

descending motor control pathway, originating in the red nucleus, that mediates control of the limbs on the basis of cerebellar processing

saccule

structure of the inner ear responsible for transducing linear acceleration in the vertical plane

scala tympani

portion of the cochlea that extends from the apex to the round window

scala vestibuli

portion of the cochlea that extends from the oval window to the apex

sclera

white of the eye

semicircular canals

structures within the inner ear responsible for transducing rotational movement information

sensory homunculus

topographic representation of the body within the somatosensory cortex demonstrating the correspondence between neurons processing stimuli and sensitivity

sensory modality

a particular system for interpreting and perceiving environmental stimuli by the nervous system

solitary nucleus

medullar nucleus that receives taste information from the facial and glossopharyngeal nerves

somatosensation

general sense associated with modalities lumped together as touch

special sense

any sensory system associated with a specific organ structure, namely smell, taste, sight, hearing, and balance

spinal trigeminal nucleus

component of the trigeminal nuclei that is found in the medulla

spinothalamic tract

ascending tract of the spinal cord associated with pain and temperature sensations

spiral ganglion

location of neuronal cell bodies that transmit auditory information along the eighth cranial nerve

stapes

(also, stirrup) ossicle of the middle ear that is attached to the inner ear

stereocilia

array of apical membrane extensions in a hair cell that transduce movements when they are bent

stretch reflex

response to activation of the muscle spindle stretch receptor that causes contraction of the muscle to maintain a constant length

submodality

specific sense within a broader major sense such as sweet as a part of the sense of taste, or color as a part of vision

superior colliculus

structure in the midbrain that combines visual, auditory, and somatosensory input to coordinate spatial and topographic representations of the three sensory systems

superior oblique

extraocular muscle responsible for medial rotation of the eye

superior rectus

extraocular muscle responsible for looking up

supplemental motor area

cortical area anterior to the primary motor cortex that is responsible for planning movements

suprachiasmatic nucleus

hypothalamic target of the retina that helps to establish the circadian rhythm of the body on the basis of the presence or absence of daylight

taste buds

structures within a papilla on the tongue that contain gustatory receptor cells

tectorial membrane

component of the organ of Corti that lays over the hair cells, into which the stereocilia are embedded

tectospinal tract

extrapyramidal connections between the superior colliculus and spinal cord

thermoreceptor

sensory receptor specialized for temperature stimuli

topographical

relating to positional information

transduction

process of changing an environmental stimulus into the electrochemical signals of the nervous system

trochlea

cartilaginous structure that acts like a pulley for the superior oblique muscle

tympanic membrane

ear drum

umami

taste submodality for sensitivity to the concentration of amino acids; also called the savory sense

utricle

structure of the inner ear responsible for transducing linear acceleration in the horizontal plane

vascular tunic

middle layer of the eye primarily composed of connective tissue with a rich blood supply

ventral posterior nucleus

nucleus in the thalamus that is the target of gustatory sensations and projects to the cerebral cortex

ventral stream

connections between cortical areas from the occipital lobe to the temporal lobe that are responsible for identification of visual stimuli

vestibular ganglion

location of neuronal cell bodies that transmit equilibrium information along the eighth cranial nerve

vestibular nuclei

targets of the vestibular component of the eighth cranial nerve

vestibule

in the ear, the portion of the inner ear responsible for the sense of equilibrium

vestibulo-ocular reflex (VOR)

reflex based on connections between the vestibular system and the cranial nerves of eye movements that ensures images are stabilized on the retina as the head and body move

vestibulospinal tract

extrapyramidal connections between the vestibular nuclei in the brain stem and spinal cord that modulate movement and contribute to balance on the basis of the sense of equilibrium

visceral sense

sense associated with the internal organs

vision

special sense of sight based on transduction of light stimuli

visual acuity

property of vision related to the sharpness of focus, which varies in relation to retinal position

vitreous humor

viscous fluid that fills the posterior chamber of the eye

working memory

function of the prefrontal cortex to maintain a representation of information that is not in the immediate environment

zonule fibers

fibrous connections between the ciliary body and the lens

Chapter 15 - Key Terms

acetylcholine (ACh)

neurotransmitter that binds at a motor end-plate to trigger depolarization

adrenal medulla

interior portion of the adrenal (or suprarenal) gland that releases epinephrine and norepinephrine into the bloodstream as hormones

adrenergic

synapse where norepinephrine is released, which binds to α- or β-adrenergic receptors

afferent branch

component of a reflex arc that represents the input from a sensory neuron, for either a special or general sense

agonist

any exogenous substance that binds to a receptor and produces a similar effect to the endogenous ligand

alpha (α)-adrenergic receptor

one of the receptors to which epinephrine and norepinephrine bind, which comes in two subtypes: α1 and α2

antagonist

any exogenous substance that binds to a receptor and produces an opposing effect to the endogenous ligand

anticholinergic drugs

drugs that interrupt or reduce the function of the parasympathetic system

autonomic tone

tendency of an organ system to be governed by one division of the autonomic nervous system over the other, such as heart rate being lowered by parasympathetic input at rest

baroreceptor

mechanoreceptor that senses the stretch of blood vessels to indicate changes in blood pressure

beta (β)-adrenergic receptor

one of the receptors to which epinephrine and norepinephrine bind, which comes in three subtypes: β1, β2, and β3

cardiac accelerator nerves

preganglionic sympathetic fibers that cause the heart rate to increase when the cardiovascular center in the medulla initiates a signal

cardiovascular center

region in the medulla that controls the cardiovascular system through cardiac accelerator nerves and vasomotor nerves, which are components of the sympathetic division of the autonomic nervous system

celiac ganglion

one of the collateral ganglia of the sympathetic system that projects to the digestive system

central neuron

specifically referring to the cell body of a neuron in the autonomic system that is located in the central nervous system, specifically the lateral horn of the spinal cord or a brain stem nucleus

cholinergic

synapse at which acetylcholine is released and binds to the nicotinic or muscarinic receptor

chromaffin cells

neuroendocrine cells of the adrenal medulla that release epinephrine and norepinephrine into the bloodstream as part of sympathetic system activity

ciliary ganglion

one of the terminal ganglia of the parasympathetic system, located in the posterior orbit, axons from which project to the iris

collateral ganglia

ganglia outside of the sympathetic chain that are targets of sympathetic preganglionic fibers, which are the celiac, inferior mesenteric, and superior mesenteric ganglia

craniosacral system

alternate name for the parasympathetic division of the autonomic nervous system that is based on the anatomical location of central neurons in brain-stem nuclei and the lateral horn of the sacral spinal cord; also referred to as craniosacral outflow

dorsal longitudinal fasciculus

major output pathway of the hypothalamus that descends through the gray matter of the brain stem and into the spinal cord

dorsal nucleus of the vagus nerve

location of parasympathetic neurons that project through the vagus nerve to terminal ganglia in the thoracic and abdominal cavities

Edinger–Westphal nucleus

location of parasympathetic neurons that project to the ciliary ganglion

efferent branch

component of a reflex arc that represents the output, with the target being an effector, such as muscle or glandular tissue

endogenous

describes substance made in the human body

endogenous chemical

substance produced and released within the body to interact with a receptor protein

epinephrine

signaling molecule released from the adrenal medulla into the bloodstream as part of the sympathetic response

exogenous

describes substance made outside of the human body

exogenous chemical

substance from a source outside the body, whether it be another organism such as a plant or from the synthetic processes of a laboratory, that binds to a transmembrane receptor protein

fight-or-flight response

set of responses induced by sympathetic activity that lead to either fleeing a threat or standing up to it, which in the modern world is often associated with anxious feelings

G protein–coupled receptor

membrane protein complex that consists of a receptor protein that binds to a signaling molecule—a G protein—that is activated by that binding and in turn activates an effector protein (enzyme) that creates a second-messenger molecule in the cytoplasm of the target cell

ganglionic neuron

specifically refers to the cell body of a neuron in the autonomic system that is located in a ganglion

gray rami communicantes

(singular = ramus communicans) unmyelinated structures that provide a short connection from a sympathetic chain ganglion to the spinal nerve that contains the postganglionic sympathetic fiber

greater splanchnic nerve

nerve that contains fibers of the central sympathetic neurons that do not synapse in the chain ganglia but project onto the celiac ganglion

inferior mesenteric ganglion

one of the collateral ganglia of the sympathetic system that projects to the digestive system

intramural ganglia

terminal ganglia of the parasympathetic system that are found within the walls of the target effector

lesser splanchnic nerve

nerve that contains fibers of the central sympathetic neurons that do not synapse in the chain ganglia but project onto the inferior mesenteric ganglion

ligand-gated cation channel

ion channel, such as the nicotinic receptor, that is specific to positively charged ions and opens when a molecule such as a neurotransmitter binds to it

limbic lobe

structures arranged around the edges of the cerebrum that are involved in memory and emotion

long reflex

reflex arc that includes the central nervous system

medial forebrain bundle

fiber pathway that extends anteriorly into the basal forebrain, passes through the hypothalamus, and extends into the brain stem and spinal cord

mesenteric plexus

nervous tissue within the wall of the digestive tract that contains neurons that are the targets of autonomic preganglionic fibers and that project to the smooth muscle and glandular tissues in the digestive organ

muscarinic receptor

type of acetylcholine receptor protein that is characterized by also binding to muscarine and is a metabotropic receptor

mydriasis

dilation of the pupil; typically the result of disease, trauma, or drugs

nicotinic receptor

type of acetylcholine receptor protein that is characterized by also binding to nicotine and is an ionotropic receptor

norepinephrine

signaling molecule released as a neurotransmitter by most postganglionic sympathetic fibers as part of the sympathetic response, or as a hormone into the bloodstream from the adrenal medulla

nucleus ambiguus

brain-stem nucleus that contains neurons that project through the vagus nerve to terminal ganglia in the thoracic cavity; specifically associated with the heart

parasympathetic division

division of the autonomic nervous system responsible for restful and digestive functions

parasympathomimetic drugs

drugs that enhance or mimic the function of the parasympathetic system

paravertebral ganglia

autonomic ganglia superior to the sympathetic chain ganglia

postganglionic fiber

axon from a ganglionic neuron in the autonomic nervous system that projects to and synapses with the target effector; sometimes referred to as a postganglionic neuron

preganglionic fiber

axon from a central neuron in the autonomic nervous system that projects to and synapses with a ganglionic neuron; sometimes referred to as a preganglionic neuron

prevertebral ganglia

autonomic ganglia that are anterior to the vertebral column and functionally related to the sympathetic chain ganglia

referred pain

the conscious perception of visceral sensation projected to a different region of the body, such as the left shoulder and arm pain as a sign for a heart attack

reflex arc

circuit of a reflex that involves a sensory input and motor output, or an afferent branch and an efferent branch, and an integrating center to connect the two branches

rest and digest

set of functions associated with the parasympathetic system that lead to restful actions and digestion

short reflex

reflex arc that does not include any components of the central nervous system

somatic reflex

reflex involving skeletal muscle as the effector, under the control of the somatic nervous system

superior cervical ganglion

one of the paravertebral ganglia of the sympathetic system that projects to the head

superior mesenteric ganglion

one of the collateral ganglia of the sympathetic system that projects to the digestive system

sympathetic chain ganglia

series of ganglia adjacent to the vertebral column that receive input from central sympathetic neurons

sympathetic division

division of the autonomic nervous system associated with the fight-or-flight response

sympatholytic drug

drug that interrupts, or “lyses,” the function of the sympathetic system

sympathomimetic drug

drug that enhances or mimics the function of the sympathetic system

target effector

organ, tissue, or gland that will respond to the control of an autonomic or somatic or endocrine signal

terminal ganglia

ganglia of the parasympathetic division of the autonomic system, which are located near or within the target effector, the latter also known as intramural ganglia

thoracolumbar system

alternate name for the sympathetic division of the autonomic nervous system that is based on the anatomical location of central neurons in the lateral horn of the thoracic and upper lumbar spinal cord

varicosity

structure of some autonomic connections that is not a typical synaptic end bulb, but a string of swellings along the length of a fiber that makes a network of connections with the target effector

vasomotor nerves

preganglionic sympathetic fibers that cause the constriction of blood vessels in response to signals from the cardiovascular center

visceral reflex

reflex involving an internal organ as the effector, under the control of the autonomic nervous system

white rami communicantes

(singular = ramus communicans) myelinated structures that provide a short connection from a sympathetic chain ganglion to the spinal nerve that contains the preganglionic sympathetic fiber

Chapter 16 - Key Terms

accommodation

in vision, a change in the ability of the eye to focus on objects at different distances

accommodation–convergence reflex

coordination of somatic control of the medial rectus muscles of either eye with the parasympathetic control of the ciliary bodies to maintain focus while the eyes converge on visual stimuli near to the face

anterograde amnesia

inability to form new memories from a particular time forward

aphasia

loss of language function

ataxia

movement disorder related to damage of the cerebellum characterized by loss of coordination in voluntary movements

Babinski sign

dorsiflexion of the foot with extension and splaying of the toes in response to the plantar reflex, normally suppressed by corticospinal input

cerebrocerebellum

lateral regions of the cerebellum; named for the significant input from the cerebral cortex

check reflex

response to a release in resistance so that the contractions stop, or check, movement

clasp-knife response

sign of UMN disease when a patient initially resists passive movement of a muscle but will quickly release to a lower state of resistance

conduction aphasia

loss of language function related to connecting the understanding of speech with the production of speech, without either specific function being lost

conductive hearing

hearing dependent on the conduction of vibrations of the tympanic membrane through the ossicles of the middle ear

conjugate gaze

coordinated movement of the two eyes simultaneously in the same direction

convergence

in vision, the movement of the eyes so that they are both pointed at the same point in space, which increases for stimuli that are closer to the subject

coordination exam

major section of the neurological exam that assesses complex, coordinated motor functions of the cerebellum and associated motor pathways

cortico-ponto-cerebellar pathway

projection from the cerebral cortex to the cerebellum by way of the gray matter of the pons

cranial nerve exam

major section of the neurological exam that assesses sensory and motor functions of the cranial nerves and their associated central and peripheral structures

cytoarchitecture

study of a tissue based on the structure and organization of its cellular components; related to the broader term, histology

deep tendon reflex

another term for stretch reflex, based on the elicitation through deep stimulation of the tendon at the insertion

diplopia

double vision resulting from a failure in conjugate gaze

edema

fluid accumulation in tissue; often associated with circulatory deficits

embolus

obstruction in a blood vessel such as a blood clot, fatty mass, air bubble, or other foreign matter that interrupts the flow of blood to an organ or some part of the body

episodic memory

memory of specific events in an autobiographical sense

expressive aphasia

loss of the ability to produce language; usually associated with damage to Broca’s area in the frontal lobe

extrinsic muscles of the tongue

muscles that are connected to other structures, such as the hyoid bone or the mandible, and control the position of the tongue

fasciculation

small muscle twitch as a result of spontaneous activity from an LMN

fauces

opening from the oral cavity into the pharynx

fibrillation

in motor responses, a spontaneous muscle action potential that occurs in the absence of neuromuscular input, resulting from LMN lesions

flaccid paralysis

loss of voluntary muscle control and muscle tone, as the result of LMN disease

flaccidity

presentation of a loss of muscle tone, observed as floppy limbs or a lack of resistance to passive movement

flocculonodular lobe

lobe of the cerebellum that receives input from the vestibular system to help with balance and posture

gait

rhythmic pattern of alternating movements of the lower limbs during locomotion

gait exam

major section of the neurological exam that assesses the cerebellum and descending pathways in the spinal cord through the coordinated motor functions of walking; a portion of the coordination exam

gnosis

in a neurological exam, intuitive experiential knowledge tested by interacting with common objects or symbols

graphesthesia

perception of symbols, such as letters or numbers, traced in the palm of the hand

hemisection

cut through half of a structure, such as the spinal cord

hemorrhagic stroke

disruption of blood flow to the brain caused by bleeding within the cranial vault

hyperflexia

overly flexed joints

hypotonicity

low muscle tone, a sign of LMN disease

hypovolemia

decrease in blood volume

inferior cerebellar peduncle (ICP)

input to the cerebellum, largely from the inferior olive, that represents sensory feedback from the periphery

inferior olive

large nucleus in the medulla that receives input from sensory systems and projects into the cerebellar cortex

internuclear ophthalmoplegia

deficit of conjugate lateral gaze because the lateral rectus muscle of one eye does not contract resulting from damage to the abducens nerve or the MLF

intorsion

medial rotation of the eye around its axis

intrinsic muscles of the tongue

muscles that originate out of, and insert into, other tissues within the tongue and control the shape of the tongue

ischemic stroke

disruption of blood flow to the brain because blood cannot flow through blood vessels as a result of a blockage or narrowing of the vessel

jaw-jerk reflex

stretch reflex of the masseter muscle

localization of function

principle that circumscribed anatomical locations are responsible for specific functions in an organ system

medial longitudinal fasciculus (MLF)

fiber pathway that connects structures involved in the control of eye and head position, from the superior colliculus to the vestibular nuclei and cerebellum

mental status exam

major section of the neurological exam that assesses cognitive functions of the cerebrum

middle cerebellar peduncle (MCP)

large, white-matter bridge from the pons that constitutes the major input to the cerebellar cortex

motor exam

major section of the neurological exam that assesses motor functions of the spinal cord and spinal nerves

neurological exam

clinical assessment tool that can be used to quickly evaluate neurological function and determine if specific parts of the nervous system have been affected by damage or disease

paramedian pontine reticular formation (PPRF)

region of the brain stem adjacent to the motor nuclei for gaze control that coordinates rapid, conjugate eye movements

paresis

partial loss of, or impaired, voluntary muscle control

plantar reflex

superficial reflex initiated by gentle stimulation of the sole of the foot

praxis

in a neurological exam, the act of doing something using ready knowledge or skills in response to verbal instruction

procedural memory

memory of how to perform a specific task

pronator drift

sign of contralateral corticospinal lesion when the one arm will drift into a pronated position when held straight out with the palms facing upward

receptive aphasia

loss of the ability to understand received language, such as what is spoken to the subject or given in written form

red nucleus

nucleus in the midbrain that receives output from the cerebellum and projects onto the spinal cord in the rubrospinal tract

retrograde amnesia

loss of memories before a particular event

Rinne test

use of a tuning fork to test conductive hearing loss versus sensorineural hearing loss

Romberg test

test of equilibrium that requires the patient to maintain a straight, upright posture without visual feedback of position

rubrospinal tract

descending tract from the red nucleus of the midbrain that results in modification of ongoing motor programs

saccade

small, rapid movement of the eyes used to locate and direct the fovea onto visual stimuli

sensorineural hearing

hearing dependent on the transduction and propagation of auditory information through the neural components of the peripheral auditory structures

sensory exam

major section of the neurological exam that assesses sensory functions of the spinal cord and spinal nerves

short-term memory

capacity to retain information actively in the brain for a brief period of time

Snellen chart

standardized arrangement of letters in decreasing size presented to a subject at a distance of 20 feet to test visual acuity

spasticity

increased contraction of a muscle in response to resistance, often resulting in hyperflexia

spinocerebellar tract

ascending fibers that carry proprioceptive input to the cerebellum used in maintaining balance and coordinated movement

spinocerebellum

midline region of the cerebellum known as the vermis that receives proprioceptive input from the spinal cord

stereognosis

perception of common objects placed in the hand solely on the basis of manipulation of that object in the hand

stroke

(also, cerebrovascular accident (CVA)) loss of neurological function caused by an interruption of blood flow to a region of the central nervous system

superficial reflex

reflexive contraction initiated by gentle stimulation of the skin

superior cerebellar peduncle (SCP)

white-matter tract representing output of the cerebellum to the red nucleus of the midbrain

transient ischemic attack (TIA)

temporary disruption of blood flow to the brain in which symptoms occur rapidly but last only a short time

vermis

prominent ridge along the midline of the cerebellum that is referred to as the spinocerebellum

vestibulo-ocular reflex (VOR)

reflex based on connections between the vestibular system and the cranial nerves of eye movements that ensures that images are stabilized on the retina as the head and body move

vestibulocerebellum

flocculonodular lobe of the cerebellum named for the vestibular input from the eighth cranial nerve

Weber test

use of a tuning fork to test the laterality of hearing loss by placing it at several locations on the midline of the skull

Wernicke’s area

region at the posterior end of the lateral sulcus in which speech comprehension is localized

Chapter 17 - Key Terms

acromegaly

disorder in adults caused when abnormally high levels of GH trigger growth of bones in the face, hands, and feet

adenylyl cyclase

membrane-bound enzyme that converts ATP to cyclic AMP, creating cAMP, as a result of G-protein activation

adrenal cortex

outer region of the adrenal glands consisting of multiple layers of epithelial cells and capillary networks that produces mineralocorticoids and glucocorticoids

adrenal glands

endocrine glands located at the top of each kidney that are important for the regulation of the stress response, blood pressure and blood volume, water homeostasis, and electrolyte levels

adrenal medulla

inner layer of the adrenal glands that plays an important role in the stress response by producing epinephrine and norepinephrine

adrenocorticotropic hormone (ACTH)

anterior pituitary hormone that stimulates the adrenal cortex to secrete corticosteroid hormones (also called corticotropin)

alarm reaction

the short-term stress, or the fight-or-flight response, of stage one of the general adaptation syndrome mediated by the hormones epinephrine and norepinephrine

aldosterone

hormone produced and secreted by the adrenal cortex that stimulates sodium and fluid retention and increases blood volume and blood pressure

alpha cell

pancreatic islet cell type that produces the hormone glucagon

angiotensin-converting enzyme

the enzyme that converts angiotensin I to angiotensin II

antidiuretic hormone (ADH)

hypothalamic hormone that is stored by the posterior pituitary and that signals the kidneys to reabsorb water

atrial natriuretic peptide (ANP)

peptide hormone produced by the walls of the atria in response to high blood pressure, blood volume, or blood sodium that reduces the reabsorption of sodium and water in the kidneys and promotes vasodilation

autocrine

chemical signal that elicits a response in the same cell that secreted it

beta cell

pancreatic islet cell type that produces the hormone insulin

calcitonin

peptide hormone produced and secreted by the parafollicular cells (C cells) of the thyroid gland that functions to decrease blood calcium levels

chromaffin

neuroendocrine cells of the adrenal medulla

colloid

viscous fluid in the central cavity of thyroid follicles, containing the glycoprotein thyroglobulin

cortisol

glucocorticoid important in gluconeogenesis, the catabolism of glycogen, and downregulation of the immune system

cyclic adenosine monophosphate (cAMP)

second messenger that, in response to adenylyl cyclase activation, triggers a phosphorylation cascade

delta cell

minor cell type in the pancreas that secretes the hormone somatostatin

diabetes mellitus

condition caused by destruction or dysfunction of the beta cells of the pancreas or cellular resistance to insulin that results in abnormally high blood glucose levels

diacylglycerol (DAG)

molecule that, like cAMP, activates protein kinases, thereby initiating a phosphorylation cascade

downregulation

decrease in the number of hormone receptors, typically in response to chronically excessive levels of a hormone

endocrine gland

tissue or organ that secretes hormones into the blood and lymph without ducts such that they may be transported to organs distant from the site of secretion

endocrine system

cells, tissues, and organs that secrete hormones as a primary or secondary function and play an integral role in normal bodily processes

epinephrine

primary and most potent catecholamine hormone secreted by the adrenal medulla in response to short-term stress; also called adrenaline

erythropoietin (EPO)

protein hormone secreted in response to low oxygen levels that triggers the bone marrow to produce red blood cells

estrogens

class of predominantly female sex hormones important for the development and growth of the female reproductive tract, secondary sex characteristics, the female reproductive cycle, and the maintenance of pregnancy

exocrine system

cells, tissues, and organs that secrete substances directly to target tissues via glandular ducts

first messenger

hormone that binds to a cell membrane hormone receptor and triggers activation of a second messenger system

follicle-stimulating hormone (FSH)

anterior pituitary hormone that stimulates the production and maturation of sex cells

G protein

protein associated with a cell membrane hormone receptor that initiates the next step in a second messenger system upon activation by hormone–receptor binding

general adaptation syndrome (GAS)

the human body’s three-stage response pattern to short- and long-term stress

gigantism

disorder in children caused when abnormally high levels of GH prompt excessive growth

glucagon

pancreatic hormone that stimulates the catabolism of glycogen to glucose, thereby increasing blood glucose levels

glucocorticoids

hormones produced by the zona fasciculata of the adrenal cortex that influence glucose metabolism

goiter

enlargement of the thyroid gland either as a result of iodine deficiency or hyperthyroidism

gonadotropins

hormones that regulate the function of the gonads

growth hormone (GH)

anterior pituitary hormone that promotes tissue building and influences nutrient metabolism (also called somatotropin)

hormone

secretion of an endocrine organ that travels via the bloodstream or lymphatics to induce a response in target cells or tissues in another part of the body

hormone receptor

protein within a cell or on the cell membrane that binds a hormone, initiating the target cell response

hyperglycemia

abnormally high blood glucose levels

hyperparathyroidism

disorder caused by overproduction of PTH that results in abnormally elevated blood calcium

hyperthyroidism

clinically abnormal, elevated level of thyroid hormone in the blood; characterized by an increased metabolic rate, excess body heat, sweating, diarrhea, weight loss, and increased heart rate

hypoparathyroidism

disorder caused by underproduction of PTH that results in abnormally low blood calcium

hypophyseal portal system

network of blood vessels that enables hypothalamic hormones to travel into the anterior lobe of the pituitary without entering the systemic circulation

hypothalamus

region of the diencephalon inferior to the thalamus that functions in neural and endocrine signaling

hypothyroidism

clinically abnormal, low level of thyroid hormone in the blood; characterized by low metabolic rate, weight gain, cold extremities, constipation, and reduced mental activity

infundibulum

stalk containing vasculature and neural tissue that connects the pituitary gland to the hypothalamus (also called the pituitary stalk)

inhibin

hormone secreted by the male and female gonads that inhibits FSH production by the anterior pituitary

inositol triphosphate (IP3)

molecule that initiates the release of calcium ions from intracellular stores

insulin

pancreatic hormone that enhances the cellular uptake and utilization of glucose, thereby decreasing blood glucose levels

insulin-like growth factors (IGF)

protein that enhances cellular proliferation, inhibits apoptosis, and stimulates the cellular uptake of amino acids for protein synthesis

leptin

protein hormone secreted by adipose tissues in response to food consumption that promotes satiety

luteinizing hormone (LH)

anterior pituitary hormone that triggers ovulation and the production of ovarian hormones, and the production of testosterone

melatonin

amino acid–derived hormone that is secreted in response to low light and causes drowsiness