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9 Cards in this Set
- Front
- Back
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When the axon is injured it undergoes what type of degeneration? Why?
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anterograde/Wallerian degeneration because interruption of transport of essential netabolites required
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What are some of the changes that occur in degeneration axons?
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lysosomes accumulate and release hydrolytic enzymes; swelling, fragmentation of myelin then axons, mitochondira accumulate at Nodes
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The axon reaction describes the response of what structure to axonal injury?
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cell body/perikaryon/soma
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What are the changes seen in axonal injury?
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1) swelling b/c ion inbalance
2) acentric nucleus 3) Nissle bodies disperse leading to chromatolysis 4) nucleolus enlargens 5) synapses withdraw |
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What determines whether a neuron will recovery or not after axon injury?
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1) distance of lesion from cell body
2) amount of axoplasm that is lost 3) age |
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What occurs in the PNS when injured axons attempt to repair
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1) Schwann cells increase in number
2) Growth cones form and grow towards injury 3) Appropriate contact must be made 4) reconnects axons, enlargens, remyelinates |
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Recovery is dependent on what 2 things?
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1) type of injury (crush better than cut)
2) age |
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What 3 factors prevent Central axons from regenerating?
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1) astrocytic-glial scars
2) lack of guidance channels b/c no basal lamina 3) Oligodendrocytes inhibit via 2 proteins |
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What is lesion-induced synaptogenesis?
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CNS demonstrates some plasticity depending on the system injured, however full recovery is never possible
Plasticity may be beneficial or inappropriate |
