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REACTIONS TO
INJURY WITHIN THE NEURON:
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Immediately -
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1. Synaptic transmission off
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2. Cut ends pull apart and seal up, and
swell,
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due to axonal
transport in both directions
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Hours later -
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Synaptic
terminal degenerates - accumulation of NF, vesicles.
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Astroglia suround
terminal normally;
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after axotomy, interpose between
terminal and target
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and cause terminal to be pulled
away from postsynaptic
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cell.
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days
- weeks -
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5.
Myelin breaks up and leaves debris (myelin hard to break down).
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6.
Axon undergoes Wallerian degeneration
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7.
Chromatolysis - cell body swells; nissl and nucleus
eccentric.
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**If axon cut in PNS or CNS, changes
are the same.
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**The damaged neuron is affected by
injury,
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as well as the pre- and postsynaptic
neurons to it
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