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Psychology 304: Brain and Behaviour

Lecture 10

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A classmate has expressed an interest in initiating a study group after class on Fridays, in Geography 100. The study group will give students the opportunity to (a) review the material from the week, (b) explore their understanding of concepts, (c) teach others, and (d) discuss questions that are beyond the scope of this course. Interested students can meet after class today, September 30th to discuss the organization of the study group.

Reminder

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The Cells of the Nervous System

2. What are glial cells?

1. What is the structure of the neuron? (continued)

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1. describe the internal structural features of the neuron.

By the end of today’s class, you should be able to:

2. distinguish between unipolar, bipolar, and multipolar neurons.

3. identify the types and functions of glial cells.

4. describe the neurological basis of multiple schlerosis.

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Self-Test: ExternalFeatures of a Typical Neuron

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Self-Test: The InternalFeatures of a Typical Neuron

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• The internal structure of the neuron is characterized by nine features (continued):

What is the structure of the neuron? (continued)

8Photomicrograph of a Neuron Cell Body

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Synaptic vesicles: Spherical membrane packages that store neurotransmitter molecules ready for release from the terminal button.

Neurotransmitters: Molecules that are released from the terminal buttons of active neurons and influence the activity of other cells.

10Internal Features of the Terminal Button

Synaptic vesicles

Neurotransmitters

Terminal button

Mitochondrion

Microtubule

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Images of Synaptic Vesicles Produced by Electron Micrography

Mitochondria

Synaptic vesicles

Synaptic contact

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• There are three primary classes of neurons:

3. Mutlipolar neurons: Have more than two projections extending from the cell body (e.g., one axon and many dendrites). The most common type of neuron found in the CNS.

1. Unipolar (monopolar) neurons: Have one projection extending from the cell body.

2. Bipolar neurons: Have two projections extending from the cell body.

13Classes of Neurons

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Bipolar neuron

Multipolar neuron

Unipolar neuron

Dendrites Axon

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• Neurons vary substantially in size and complexity.

In contrast to small neurons, large neurons detect and transmit more information and cover greater distances.

15Variability in the Size and Complexity of Neurons

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• Found throughout the nervous system; more common than neurons.

What are glial cells?

• Surround and support neurons, control the supply of nutrients to neurons, assist in the exchange of chemicals between neurons, destroy and remove damaged neurons.

• Four types of glial cells have been identified: Oligodendrocytes, Schwann cells, microglia, astrocytes.

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Myelination of Axons in the CNS by Oligodendrocytes

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Myelination of Axons in the CNS by Oligodendrocytes vs. Myelination of Axons in the

PNS by Schwann Cells

19Microglia

20Microglia

21Structure of Astrocytes

22Astrocytes

Microglia

23Multiple Sclerosis

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The Cells of the Nervous System

2. What are glial cells?

1. What is the structure of the neuron? (continued)