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6 Cards in this Set
- Front
- Back
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What is the difference between injuries occurring in the PNS vs. the CNS?
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Injuries in the PNS often fix themselves (fibroblasts, Schwann cells facilitate recovery)
Injuries in the CNS often don't fix themselves (glial scar inhibits recovery) |
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Is there regeneration in the proximal segment?
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-Retrograde degeneration for a few segments or more
-Often regeneration in cell body |
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Is there regeneration in the distal segment?
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-Called Wallerian degeneration
-This segment dies over a couple of months -In PNS, nerve sheathe and Schwann cells remain to facilitate axon growth, but in CNS no structures remain to facilitate growth |
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How fast is axon re-growth?
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-Often occurs in PNS but almost never in CNS
-Rate is 1-2 mm per day |
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What is aberrant regeneration?
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-When some fibers of an axon grow back to the wrong place
-PNS regeneration is often successful, and aberrant regeneration is usually no more than a nuisance |
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If there is no regeneration in the CNS, why do patients with CNS lesions often show some degree of recovery of function?
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-CNS plasticity: ability of CNS to undergo modification or rearrangement
1) Unmasking of latent synapses 2) Sprouting Others: neural shock, compensation, supersensitivity, substitution |
