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Histology

…pass the tissues please…

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Outline

  1. Intro to Histology
  2. Epithelial Tissue: Anatomy
  3. Epithelial Tissue: Physiology
  4. Epithelial Tissue Types
  5. Muscle
  6. Connective Tissue Intro
  7. Connective Tissue proper
  8. Fluid Connective
  9. Supporting Connective
  10. Nervous
  11. Glands
  12. Membranes
  13. Junctions
  14. Clinical Applications

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I. Intro to Histology

  • The study of body tissues
  • Tissue definition: A group of similar cells working towards one unifying goal

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  • Tissues components
    1. Similar cells
    2. Extracellular Matrix

- water, NaCl, ions, calcium, fibers, nutrients, etc..

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I. Intro to Histology

The 4 types of tissues

    • Epithelial�        * covers body surfaces�        * lines hollow organs�        * lines body cavities and ducts�        * forms glands and secretions
    • Connective�        * protection and support�        * binding together�        * energy storage
    • Muscle

* movement and force (including peristalsis)

    • Nervous

* coordinates body activities

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I. Critical Thinking Question?

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What tissue type does blood belong to?

A. Epithelial

B. Connective

C. Muscle

D. Nerve

E. Blood isn’t a tissue

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II. Epithelial Anatomy

  • Location
    • covers every “surface”
      • Skin, GI tract, cheeks, blood vessels, organs, lungs, cavities etc…
    • Forms Glands

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II. Epithelial Anatomy

  • Basic Anatomy
    • Cells bound tightly together
    • Classified by shape of cells and number of layers
    • Avascular
    • Contain Stem cells
    • Has an exposed surface (Apical membrane)
    • Has a surface bound to connective tissue (basal membrane)

Apical Surface

Basal

(basement)

Connective

tissue

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II. Epithelial Anatomy

  • Basic Anatomy
    • Apical Surface may contain specialized structures
      • Cilia for movement
      • Microvilli for increased absorption (Brush Borders)

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II. Epithelial Anatomy

The Brush Border

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II. Epithelial Anatomy

  • Basic Anatomy
    • Basal Membrane: “Basement”
      • Provides strength to epithelium
      • Creates barriers to prevent molecules from entering connective tissue

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II. Epithelial Anatomy

  • Shape
    • Squamous: Flat
    • Cuboidal: cube-like
    • Columnar: column-like
    • Transitional: changes

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  • By Layers
    • Simple: single
    • Stratified: multiple
    • Pseudostratified: appears multiple, but really simple

Classification Systems

Example. Simple cuboidal = 1 cell thick of cube shaped cells

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  • Function
    • Provides protection internally and externally
    • Controls permeability
    • Provides for touch/stimuli
    • Produces secretions

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III. Epithelial Physiology

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IV. Epithelial Tissues: Simple Squamous

Simple Squamous

Anatomy/locations

  • Lining of body cavities, organs, blood vessels, alveoli lung surface
  • Serous Membranes

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Physiology

  • *Diffusion - Permeability
  • Absorption
  • Secretions

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IV. Epithelial Tissues: Simple Squamous

Simple Squamous

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Simple Squamous

IV. Epithelial Tissues: Simple Squamous

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IV Epithelial Tissues: Simple Cuboidal

Simple Cuboidal

Anatomy/Location

  • Digestive tract, Kidney tubules, glands

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Physiology

  • Limited protection
  • Absorption and Secretions

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IV Epithelial Tissues: Simple Cuboidal

Simple Cuboidal

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IV Epithelial Tissues: Simple Columnar

Simple Columnar

Anatomy

  • Lining of digestive tract
  • Modified by presence of cilia
  • Contains “Goblet cells”
    • Secrete mucus to protect against digestive enzymes
    • High concentration after the stomach

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IV Epithelial Tissues: Simple Columnar

Physiology

  • Help move surface material
  • Absorption and Secretion
  • Protection (stomach)

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IV Epithelial Tissues: Simple Columnar

Simple Columnar

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Simple Columnar

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IV Epithelial Tissues: Simple Cuboidal

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IV Epithelial Tissues: Simple Columnar

Simple Columnar

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IV Epithelial Tissues: Simple Columnar

  • Ciliated Simple Columnar
    • Found in the spinal cord lining the serous membranes
      • Circulate Cerebrospinal Fluid (CSF)
      • Fallopian tubes
  • Simple Columnar with microvilli
    • Found in the intestinal tract

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IV Epithelial Tissues: Pseudostratified Columnar

Pseudostratified Columnar

Anatomy

  • One layer
  • All attach to the basal membrane
  • Appears stratified
  • contains cilia
  • Upper respiratory tract

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Physiology

  • Move material
  • Secretion

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IV Epithelial Tissues: Pseudostratified Columnar

Pseudostratified Columnar

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IV Epithelial Tissues: Stratified Squamous

Stratified Squamous

Anatomy

  • Outer most layer- squamous cells
  • Inner- cuboidal or columnar
  • Lining of mouth, esophagus, skin
  • Can be keratinized

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Physiology

  • Phys/Chem Protection
  • Secretion
  • Moistens membranes

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IV Epithelial Tissues: Stratified Squamous

Stratified Squamous – non keratinized

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IV Epithelial Tissues: Stratified Squamous

Keratinized Stratified Squamous

  • Keratin: Waxy-like protective coverings
  • Creates a moisture barrier

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IV Epithelial Tissues: Transitional Epithelia

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Transitional Epithelial

Anatomy

  • Located in bladder
  • Multiple Layers
  • Changes from cuboidal to squamous shape
  • Layers can go from 5-7 cell layers thick to 3-4 without structural damage

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Physiology

  • Allows for stretching (distended)

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V: Muscle

Three types

1. Skeletal

2. Smooth

3. Cardiac

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Functions:

  • Cells have ability to contract to produce force
  • Locomotion and body movements
  • Support and posture
  • Peristalsis

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V: Muscle: Skeletal

Anatomy/Location

  • Attached to Bones
  • Long and cylindrical
  • Transverse striation
  • multi-nucleated

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Physiology

  • Voluntary movement
  • Heat production

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Anatomy/Location

  • Lining blood vessels and digestive Tract
    • Longitudinal/circumferential
  • Short and spindle shape
  • Single nucleus

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Physiology

  • Involuntary movement
  • Peristalsis

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V: Muscle: Smooth

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Anatomy/Location

  • Heart muscle
  • Striations
  • Intercalated disks
  • Short, branched cells

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Physiology

  • Involuntary
  • Circulates blood, maintains blood pressure

V: Muscle: Cardiac

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V: Muscle: Cardiac

  • Muscle Cell Images

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VI. Connective Tissue Intro

  • Abundant extracellular material
    • Matrix (dominant part) or ground substance
      • Fibers: Strength and elasticity
      • Can be liquid, gel-like, or solid matrix
    • Never exposed to “outside environment”
      • If exposed, causes a response for “damage control” (ie. Bleeding and blood clotting)
  • Functions
    • Bind and/or support other tissue
    • Energy storage, energy conservation
    • Protection for the body
    • Defense: antibody production, cell-to-cell “combat”

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Classified according to the matrix…

  1. Connective Tissue Proper – A syrupy mix of cells and fibers (ie. subcutaneous, fat, tendons and ligaments)

*CT. Proper is subdivided into Loose, or Dense

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2. Fluid connective tissue – cells suspended in liquid (ie. Blood and lymph)

3. Supporting connective tissue – closely packed fibers or minerals (ie. Bone, cartilage)

VI. Connective Tissue Intro

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Connective Tissue

Tissue Proper

Fluid

Supporting

Blood

Lymph

Cartilage

Bone

Dense Regular

Dense

Loose

Dense Irregular

VI. Connective Tissue Intro

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VI. Connective Tissue Intro

Composition of Tissue Proper

Cells that make up Tissue Proper…

  • Fibroblasts – homeostasis of tissue
  • Macrophages – engulf waste
  • Fat cells – permanent residents
  • Mast cells – near blood vessels, release chemicals to elicit injury response

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VI. Connective Tissue Intro

  • Fibers in Tissue Proper…
    • Collagen - Thick, strong, and flexible
    • Elastin - Allow for stretching and recoil
      • examples: Ligaments and lining arteries

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VII. Kinds of Tissue Proper

Loose Connective

  • Areolar
    • named for airy appearance
    • Cushions and support
    • Examples: subcutaneous (deep to skin), between muscles, around vessels, nerves, organs, etc

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Loose Connective

  • Adipose (Fat)
    • Stores large fat droplets
    • Large “marshmallow” looking cells
    • Nuclei squished to one side

VII. Kinds of Tissue Proper

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VII. Kinds of Tissue Proper

Dense Connective

    • Contain collagen fibers (strength)
    • Can be Regular or Irregular
  • Dense Regular
    • Collagen packed tightly in parallel
    • Aligned with forces
    • Tendons: mostly collagen fibers
    • Ligaments: includes elastin fibers
    • Provides attachments
  • Dense Irregular
    • provides support and strength
    • Dermis of the skin

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Dense Regular

Dense

Dense Irregular

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VII. Kinds of Tissue Proper

  • Dense Regular

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  • Dense Irregular

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  • Blood
    • Plasma: Liquid matrix
    • RBC’s
    • WBC’s
    • Functions
      • Transport
      • diffusion into interstitial fluids
  • Lymphatic System
    • Lymph: fluid portion
    • Part of your immune system

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VIII. Fluid Connective Tissue

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  • Cartilage Connective Tissue
    • Rubbery consistency (matrix)
    • Avascular

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IX. Supporting Connective

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Types of Cartilage

  • Hyaline – most common
    • Joints, rib cage, respiratory tract
  • Elastic
    • Mostly elastic fibers, very flexible
    • Outer ear, nose, epiglottis
  • Fibrocartilage
    • Mostly collagen fibers, durable, strong, tough
    • Locations:

IX. Supporting Connective

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  • Bone
    • Osteocytes: bone cells
    • Hardest connective tissue
    • Compact Bone
      • Shafts of long bones and edges
      • Tightly organized
    • Spongy bone
      • Made of tiny “needles” of bone”
      • Ends of long bones

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IX. Supporting Connective

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Compact Bone

Compact Bone

Spongy Bone

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Connective Tissue

Tissue Proper

Fluid

Supporting

Blood

Lymph

Cartilage

Bone

Dense Regular

Dense

Loose

Dense Irregular

VI. Connective Tissue Intro

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  • Cells with a high ability to
    • Respond to stimuli
    • Transmit impulses
  • Two types of cells
    • Neurons – conduct nerve impulses (like wires)
      • Can these divide by mitosis? ____
    • Neuroglia – “Glial” cells provide physical support, maintain chemical composition of tissue fluids, nutrients… (like electricians)
      • can these divide by mitosis? ____

X: Nervous Tissue

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Neuron structures

  • Cell Body
  • Nucleus
  • Dendrites
  • Axon

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  • Axons can be very long
  • Use action potentials to communicate (the body's “electrical system”)

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X: Nervous