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Anatomical subdivisions of NS
Made up of neurons
and neuroglia cells
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Functional Overview of NS
CNS
Integration,
processing and
coordination of
sensory data andmotor commands
Higher functions
PNS
1. Sensory or afferent division
with sensory neurons.
Brings sensory info to CNS.
Begins as receptors, ends
in?
2. Motor or efferent division
with motor neurons.Brings motor commands to
peripheral tissue.
Ends at effector cells.
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Peripheral Nervous System
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Cellular Organization of Neural Tissue
Two cell types:
1. Neurons
2. Neuroglia
Schwann cells
Satellite cells
Astrocytes Oligodendrocytes
Microglial cells
Ependymal cells
See fig. 13-5
Compare to fig. 14-4
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General Neuron Structure
Cell body or Soma with Perikaryon
Dendrites
Axon with axon hillock
Synaptic terminals
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Astrocytes: largest & most numerous
Function:
BBB
structural framework & repairs
regulation of ions, nutrients, gases
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Oligodendrocyte
Smaller than astrocyte
Produce myelin in CNS (white matter vs. gray matter! )
Myelin = ?
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Microglia cells
Smallest
Phagocytosis of ?
# during infection
or injury
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Ependymal
cellsLining of ventricles & central canal
Some regions ciliated
Some specialized to produce CSF
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Schwann Cells
and Peripheral Axons
myelinated
Responsible for
myelination, but
surround all peripheral
axons!
Involved in repair
mechanism after injury
Wallerian Degeneration
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Structural Neuron Classification
Anaxonic
In CNS
UnipolarAlso called
pseudounipolarSensory neurons
Axon hillock
See fig. 13-10
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Structural Neuron Classification cont. . .
BipolarUnmyelinated
Rare, but importantin special senses
MultipolarMost common
All motor neurons
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Functional Neuron Classification
1) somatic vs.
visceral sensory
or afferent
monitoring of ?
2) somatic vs.
visceral motor
or efferentcarry instructions to ?
3) Inter- or
association neurons
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Synapse
Site of communication between two nervecells or nerve cell and effector cell
neuro-effector junctions
(example?)
Electrical vs.
chemical synapses
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Anatomical Organizatin of NS
Collections of cell bodies - ganglion in PNS, center or
nucleus in CNS
Bundles of axons - tracts in CNS, nerves in PNS
“White” = myelinated axons, both nerves and tracts
“Gray” = non-myelinated material, dendrites,synapses and cell bodies as well as nonmyelinated
axons. In CNS – nucleus; in PNS - ganglia
Compare to fig. 13-15