Unit 3: Biological Psychology

Essential Task 3-1:

Identify the basic parts of the neuron (dendrites, cell body, axon, terminal buttons, synaptic vesicles, and receptor sites)

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AP Psychology

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Essential Task 3-1:

• Biological Psychology defined
• Principles of Bio Psych
• Basic parts of the neuron
• Dendrites (Receptor sites)
• Cell body
• Axon (Myelin Sheath Myelin Sheath and Glial CellsMyelin Sheath and Glial Cells (White vs. Gray Matter) )
• Terminal buttons (Synaptic vesicles)
• Synapse
• Terminal buttons (Synaptic vesicles)
• Neurotransmitters
• Synaptic Cleft/Space
• Receptor Sites

Outline

Biological Psychology

• branch of psychology that studies how the body influences behavior and mental processes
• some biological psychologists call themselves behavioral neuroscientists, neuropsychologists, behavior geneticists, physiological psychologists, or biopsychologists

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Biological Psychology

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Principles of Biological Psychology

• Everything psychological is simultaneously biological.
• The nervous system is complexity built from simplicity.
• The brain is both specialized and integrated.
• The nervous system is “plastic” especially at early ages of development.

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Neurons: The Messengers

• About 100 billion neurons (nerve cells) in the human brain. Recent estimates put it at about 86 billion.
• About 100 trillion connections amongst these neurons.
• Neurons have many of the same features as other cells
• Nucleus
• Cytoplasm
• Cell membrane
• What makes neurons unique is their shape and function

Outline

Brain Activity Map Project

• Started in 2013 this project is going to attempt to map the connection of every neuron in a human brain by 2023
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Outline

Images of neurons

There are approximately 100 billion (100,000,000,000) neurons in the human brain. To get an idea of how many 100 billion is, think of this:

Assume that you were going to count all 100 billion cells at a rate of 1 cell per second. How long would it take you to count all 100 billion cells? My calculations say it would take about 3,171 years!. Do the math yourself. (Here is a hint on the math: there are 60 seconds in a minute; 60 minutes in an hour; 24 hours in a day; 365 days in a year.) By the way, my calculations did NOT take "leap years" into account. Actually, it would probably take a lot longer than 3,171 years because it takes more than 1 second to say the large numbers.

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Here is another way to think of 100 billion:

Assume the cell body of one neuron is 10 microns wide (this is just an assumption because neurons come in many different sizes. However, 10 microns is small; smaller than the period at the end of this sentence). Ok...if you were able to line up all 100 billion neurons in a straight line, how long would your line be? Check my math!!

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1 neuron = 10 microns wide

10 neurons = 100 microns wide

100 neurons = 1000 microns wide = 1 mm wide

1,000 neurons = 10 mm wide = 1 cm wide

100,000 neurons = 100 cm wide = 1 m wide

100,000,000 neurons = 1000 m = 1 km

10,000,000,000 neurons = 100 km

100,000,000,000 neurons = 1000 km (approximately 600 miles)

Although all the neurons lined up side by side would stretch 1000 km, the line would be only 10 microns wide...invisible to the naked eye!!!

To get an idea of how small a neuron is, let's do some more math:

The dot on top of this "i" is approximately 0.5 mm (500 microns or 0.02 in) in diameter. Therefore, if you assume a neuron is 10 microns in diameter, you could squeeze in 50 neurons side-by-side across the dot. However, you could squeeze in only 5 large (100 micron diameter) neurons.

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Some neurons are very short...less than a millimeter in length. Some neurons are very long...a 40 inches or more! The axon of a motor neuron in the spinal cord that innervates a muscle in the foot can be about 1 meter (3 feet) in length.

Think about how long the axon of a motor neuron would be if you wanted to make a model of it. The cell body of a motor neuron is approximately 100 microns (0.1 millimeter) in diameter and as you now know, the axon is about 3 feet (1,000 millimeter) in length. So, the axon of a motor neuron is 10,000 times as long as the cell body is wide. If you use a ping-pong ball (diameter = ~3.8 cm or 1.5 inch) to model the cell body, your axon would have to be 38,000 cm (380 meters) or 1,247 feet in length. If you use a basketball (diameter = ~24 cm or 9.5 inch) as the cell body, then your axon would have to be 240,000 cm (2.4 kilometers) or 7874 ft (1.49 miles) in length!

Neural Communication

Outline

Action Potential/Resting Potential

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Polarization.Depolarization

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Sodium/Potassium

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Outline

The longest part of a motor neuron is likely to be the

a. dendrite.

b. axon.

c. cell body.

d. synapse.

e. neurotransmitter

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Crash Course: Edpuzzle (2 different episodes)

The Synapse

• The synapse
• Composed of the terminal button of one neuron, the synaptic space, and the dendrites or cell body of the receiving neuron
• Terminal button
• Enlarged area at the end of an axon
• Synaptic space (synaptic cleft)
• Tiny gap between neurons
• Receptor Sites
• Sites on the dendrite of the receiving neuron where neurotransmitters bind fitting like keys into specially designed locks.

Outline

Chemical Transmission Between Neurons

• Synaptic vesicles release neurotransmitters that bind to receptor sites.
• Sacs in terminal button that release chemicals into synaptic space
• Chemicals released by synaptic vesicles
• Sites on the dendrite of the receiving neuron where neurotransmitters bind fitting like keys into specially designed locks.

Outline

Chemical Transmission BETWEEN Neurons

Outline

In transmitting sensory information to the brain, an electrical signal travels from the ________ of a single neuron.

a. cell body to the axon to the dendrites

b. dendrites to the axon to the cell body

c. axon to the cell body to the dendrites

d. dendrites to the cell body to the axon

e. axon to the dendrites to the cell body

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Types of Neurons

• Sensory neurons
• Carry information from sensory systems to the brain
• Also referred to as afferent (arrives)
• Motor neurons
• Carry information from the brain to muscles and glands
• Also referred to as efferent (exits)
• Interneurons
• Carry information between other neurons found only within brain and spinal cord

Outline

As you are reading this question, the cells in your eyes are firing in response to the light coming from this paper. Which type of neuron is carrying this message to the brain?

a. interneuron

b. sensory

c. presynaptic

d. motor

e. efferent

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Glial Cells

• Cells that insulate and support neurons
• Create the myelin sheath
• Remove waste products
• Provide nourishment
• Prevent harmful substances from entering the brain
• Forms white matter in the brain helping communication across the brain
• Gray matter is in myelinated brain tissue.

Outline

White and Gray Matter

Nodes of Ranvier- Gaps in the myelin sheath that enable the action potential in a neuron

Neuroplasticity Overview

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Another Video that overviews (better in Cognition unit)

When it doesn’t work... Concussion video

Neuron Candy Activity instructions

Handout