1. 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)
Dendrites
Cell body
Nuclei of
neuroglia
Axon
© Ed Reschke

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

3. 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

4. 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)

5. Functions of Nervous System
Sensory Function (receiving information)
Sensory receptors gather information
Information is carried to the CNS
Integrative Function (deciding what to do about information)
Sensory information used to create:
Sensations
Memory
Thoughts
Decisions
Motor Function (acting on information)
Decisions are acted upon
Impulses are carried to effectors

6. 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

7. 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)
Nucleus of
Schwann cell
Axon
Schwann
cell
Portion of a
collateral

8. 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

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

10. Classification of Neurons: Functional Differences
Sensory Neurons
Afferent (approach)
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 in CNS
Aka association neurons
Multipolar
Cell body
Axon
(central process)
Axon
(peripheral process)
Sensory (afferent) neuron
Interneurons
Motor (efferent) neuron
Motor Neurons
Efferent (exit)
Carry impulses away from CNS to effectors
Multipolar
Axon
Effector
(muscle or gland)
Axon
Axon
terminal

11. 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)

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

13. 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

14. 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 of
postsynaptic
neuron
Axon of
presynaptic
neuron
Cell body of
postsynaptic
neuron
Impulse
Impulse

15. 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)