1. Chapter 10
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2. 10.1: Introduction Cell types in neural tissue: Neurons
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Cell types in neural tissue:
Neurons
Neuroglial cells (also known as neuroglia, glia, and glial cells)
Dendrites
Cell body
Nuclei of
neuroglia
Axon
© Ed Reschke

3. Divisions of the Nervous System
Central Nervous System (CNS)
Brain
Spinal cord
Peripheral Nervous System (PNS)
Cranial nerves
Spinal nerves

4. Divisions of Peripheral Nervous System
Sensory Division
Picks up sensory information and delivers it to the CNS
Motor Division
Carries information to muscles and glands
Divisions of the Motor Division:
Somatic – carries information to skeletal muscle
Autonomic – carries information to smooth muscle, cardiac muscle, and glands

5. Divisions Nervous System
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Central Nervous System
(brain and spinal cord)
Peripheral Nervous System
(cranial and spinal nerves)
Brain
Cranial
nerves
Sensory division
Sensory receptors
Spinal
cord
Spinal
nerves
Motor division
Somatic
Nervous
System
Skeletal muscle
Autonomic
Nervous
System
Smooth muscle
Cardiac muscle
Glands
(a)
(b)

6. 10.2: General Functions of the Nervous System
The three general functions of the nervous system:
Receiving stimuli = sensory function
Deciding about stimuli = integrative function
Reacting to stimuli = motor function

7. Functions of Nervous System
Sensory Function
Sensory receptors gather information
Information is carried to the CNS
Integrative Function
Sensory information used to create:
Sensations
Memory
Thoughts
Decisions
Motor Function
Decisions are acted upon
Impulses are carried to effectors

8. 10.3: Description of Cells of the Nervous System
Neurons vary in size and shape
They may differ in length and size of their axons and dendrites
Neurons share certain features:
Dendrites
A cell body
An axon

9. Neuron Structure Chromatophilic substance (Nissl bodies) Dendrites
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Chromatophilic
substance
(Nissl bodies)
Dendrites
Cell body
Nucleus
Nucleolus
Neurofibrils
Axonal
hillock
Impulse
Axon
Synaptic knob of
axon terminal
Nodes of Ranvier
Myelin (cut)
Schwann
cell
Nucleus of
Schwann cell
Axon
Portion of a
collateral

10. Myelination of Axons White Matter Contains myelinated axons
Considered fiber tracts
Gray Matter
Contains unmyelinated structures
Cell bodies, dendrites
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Dendrite
Unmyelinated
region of axon
Myelinated region of axon
Node of Ranvier
Axon
Neuron
cell body
Neuron
nucleus
(a)
Enveloping
Schwann cell
Schwann
cell nucleus
Longitudinal
groove
Unmyelinated
axon
(c)

11. 10.4: Classification of Neurons and Neuroglia
Neurons vary in function
They can be sensory, motor, or integrative neurons
Neurons vary in size and shape, and in the number of axons and dendrites that they may have
Due to structural differences, neurons can be classified into three (3) major groups:
Bipolar neurons
Unipolar neurons
Multipolar neurons

12. Classification of Neurons: Structural Differences
Bipolar neurons
Two processes
Eyes, ears, nose
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Dendrites
Unipolar neurons
One process
Ganglia of PNS
Sensory
Peripheral
process
Axon
Multipolar neurons
99% of neurons
Many processes
Most neurons of CNS
Direction
of impulse
Central
process
Axon
Axon
(a) Multipolar
(b) Bipolar
(c) Unipolar

13. Classification of Neurons: Functional Differences
Sensory Neurons
Afferent
Carry impulse to CNS
Most are unipolar
Some are bipolar
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Central nervous system
Peripheral nervous system
Cell body
Dendrites
Sensory
receptor
Interneurons
Link neurons
Aka association neurons or internuncial neurons
Multipolar
Located in CNS
Cell body
Axon
(central process)
Axon
(peripheral process)
Sensory (afferent) neuron
Interneurons
Motor (efferent) neuron
Axon
Effector
(muscle or gland)
Axon
Motor Neurons
Multipolar
Carry impulses away from CNS
Carry impulses to effectors
Axon
terminal

14. Types of Neuroglial Cells in the PNS
1) Schwann Cells
Produce myelin found on peripheral myelinated neurons
Speed up neurotransmission
2) Satellite Cells
Support clusters of neuron cell bodies (ganglia)

15. Types of Neuroglial Cells in the CNS
1) Microglia
CNS
Phagocytic cell
3) Oligodendrocytes
CNS
Myelinating cell
2) Astrocytes
CNS
Scar tissue
Mop up excess ions, etc.
Induce synapse formation
Connect neurons to blood vessels
Part of Blood Brain Barrier
4) Ependyma or ependymal
CNS
Ciliated
Line central canal of spinal cord
Line ventricles of brain

16. Types of Neuroglial Cells
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Fluid-filled cavity
of the brain or
spinal cord
Neuron
Ependymal
cell
Oligodendrocyte
Astrocyte
Microglial cell
Axon
Myelin
sheath (cut)
Capillary
Node of
Ranvier

17. Regeneration of A Nerve Axon
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Motor neuron
cell body
Skeletal
muscle fiber
Changes
over time
Site of injury
Schwann cells
Axon
(a)
Distal portion of
axon degenerates
(b)
Proximal end of injured axon
regenerates into tube of sheath cells
(c)
Schwann cells
degenerate
(d)
Schwann cells
proliferate
(e)
Former connection
reestablished

18. 10.5: The Synapse
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Nerve impulses pass from neuron to neuron at synapses, moving from a pre-synaptic neuron to a post-synaptic neuron.
Synaptic
cleft
Impulse
Dendrites
Axon of
presynaptic
neuron
Axon hillock of
Postsynaptic neuron
Axon of
presynaptic
neuron
Cell body of
postsynaptic
neuron
Impulse
Impulse

19. Synaptic Transmission
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Direction of
nerve impulse
Neurotransmitters are released when impulse reaches synaptic knob
Synaptic
vesicles
Axon
Presynaptic neuron
Ca+2
Ca+2
Synaptic knob
Cell body or dendrite
of postsynaptic neuron
Mitochondrion
Synaptic
vesicle
Ca+2
Vesicle releasing
neurotransmitter
Axon
membrane
Neurotransmitter
Synaptic cleft
Polarized
membrane
Depolarized
membrane
(a)