Download What is the structure of the neuron? (continued)

Psychology 304:
Brain and Behaviour
Lecture 10
1
From a classmate ....
A YouTube clip that may provide an amusing mnemonic for
recalling brain structures:
http://www.youtube.com/watch?v=fh5hjbQWQ78&feature=
related
2
The Cells of the Nervous System
1. What is the structure of the neuron? (continued)
2. What are glial cells?
3
By the end of today’s class, you should be able to:
1. describe the external structural features of the neuron.
2. describe the internal structural features of the neuron.
3. distinguish between unipolar, bipolar, multipolar, and
inter-neurons.
4. identify the types and functions of glial cells.
4
What is the structure of the neuron? (continued)
• The external structure of the neuron is characterized by
eight features:
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Dendrite
Terminal button
Cell body
Axon
Cell membrane
Nodes of
Ranvier
Myelin sheath
Axon hillock
External Features of a Typical Neuron
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Image of a Neuron Produced by
Light Microscopy
7
• The internal structure of the neuron is characterized by
nine features:
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Golgi complex
Endoplasmic
reticulum
Ribosomes
Internal Features of the Cell Body
9
Photomicrograph of a Neuron Cell Body
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Terminal button
Microtubule
Mitochondrion
Synaptic vesicles
Neurotransmitters
Internal Features of the Terminal Button
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Synaptic contact
Mitochondria
Synaptic vesicles
Images of Synaptic Vesicles
Produced by Electron Micrography
12
• With respect to number of processes (i.e., projections),
there are four primary classes of neurons:
1. Unipolar (monopolar) neurons: Have one projection
extending from the cell body.
2. Bipolar neurons: Have two projections extending
from the cell body.
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3. Multipolar neurons: Have more than two projections
extending from the cell body—typically, one axon
and many dendrites. The most common type of
neuron in the CNS.
4. Interneurons: Have a short axon or no axon. The
primary function of interneurons is to integrate
neural signals.
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Unipolar
Bipolar
Multipolar
Interneuron
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• Neurons vary substantially in size and complexity.
In contrast to small neurons, large neurons detect and
transmit more information, cover greater distances,
and convey information between cells more rapidly.
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Variability in the Size and Complexity of Neurons
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What are glial cells?
• Found throughout the nervous system; more common
than neurons.
• 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
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The Cells of the Nervous System
1. What is the structure of the neuron? (continued)
2. What are glial cells?
21