1. Chapter 7 The Nervous System
Essentials of Human Anatomy & Physiology
Seventh Edition
Elaine N. Marieb
Chapter 7 The Nervous System
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

2. Functions of the Nervous System
1) Sensory input – gathering information
To monitor changes occurring inside and outside the body
Changes = stimuli
2) Integration
To process and interpret sensory input and decide if action is needed
Slide 7.1a
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3. Functions of the Nervous System
3) Motor output
A response to integrated stimuli
The response activates muscles or glands
Slide 7.1b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

4. Structural Classification of the Nervous System
1) Central nervous system (CNS)
Brain
Spinal cord
2) Peripheral nervous system (PNS)
Nerve outside the brain and spinal cord
Spinal nerves and cranial nerves
Slide 7.2
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

5. Functional Classification of the Peripheral Nervous System
1) Sensory (afferent) division
Nerve fibers that carry information to the central nervous system
Figure 7.1
Slide 7.3a
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6. 2) Motor (efferent) division
Nerve fibers that carry impulses away from the central nervous system
Two subdivisions
1) Somatic nervous system = voluntary
2) Autonomic nervous system = involuntary
Figure 7.1
Slide 7.3b
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7. Organization of the Nervous System
Figure 7.2
Slide 7.4
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8. Nervous Tissue: Support Cells (CNS)
Neuroglia – supporting cells of the CNS
Astrocytes – star-shaped cells that brace and anchor neurons to capillaries
Microglia – spider-like phagocytes that dispose of debris
Ependymal cells – line cavities of the brain and spinal cord and have cilia that help circulate cerebrospinal fluid
Oligodendrocytes – wrap their flat extensions around nerve fibers, producing myelin sheaths
- Myelin sheath – fatty insulating covering
Slide 7.7b

9. Nervous Tissue: Support Cells
**Figure 7.3
p205
Slide 7.7b
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10. Nervous Tissue: Support Cells (PNS)
Schwann cells
Form myelin sheath in the peripheral nervous system
Figure 7.3e
Slide 7.7b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

11. Nervous Tissue: Neurons
Neurons = nerve cells
Cells specialized to transmit messages
2 Major regions of neurons
1) Cell body
2) Processes
Slide 7.8
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12. Neuron Anatomy 1) Cell body – nucleus and metabolic center of the cell
Figure 7.4a
Slide 7.9b
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13. Neuron Anatomy 2) Processes – fibers that extend from the cell body
a. Dendrites – conduct impulses toward the cell body
b. Axons – conduct impulses away from the cell body
Figure 7.4a
Slide 7.10
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

14. Axons and Nerve Impulses
Axons end in axonal terminals
Axonal terminals contain vesicles with neurotransmitters
Axonal terminals are separated from the next neuron by a gap
Synaptic cleft – gap between adjacent neurons
Synapse – junction between nerves
Slide 7.11
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

15. Nerve Fiber Coverings
Schwann cells – produce myelin sheaths in jelly-roll like fashion
Nodes of Ranvier – gaps in myelin sheath along the axon
Figure 7.5
Slide 7.12
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

16. Neuron Cell Body Location
Most are found in the central nervous system (better protected)
Gray matter – cell bodies and unmylenated fibers
White matter – mylenated fibers
Nuclei – clusters of cell bodies within the white matter of the central nervous system
Ganglia – collections of cell bodies outside the central nervous system
Slide 7.13
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings