injury and repair in the NS Flashcards
what are the processes that follow a peripheral nerve injury
degeneration (maybe regeneration)
development of neuropathic pain
where is the cell body of sensory nerve found
dorsal root ganglion
where is the cell body of the motor nerve found
ventral horn of SC
what occurs if there is damage to peripheral nerve
periphery part looses connection to cell body
cannot survive therefore degenerates
(distal stump - peripheral part)
explain process of wallerian regereration
severing of the axon result in fragmentation of distal axon and myelin sheath
Schwann cells proliferate and macrophages invade distal nerve segment
phagocytose degrading materials
Schwann cells (in distal segment) line up in bands of Bugner
axonal sprouts (in Schwann cells) are attracted by gradients of neurotrophic factors
axonal reconnection with end organs
what produce the neurotrophic factors
Schwann cells
why is repair of the IAN less likely to fail
found in the bony canal
ends less able to spring apart
what is a neuroma
swelling of a nerve
what happens if a nerve is unable to regernate to e.g. muscle
gap between central and distal too large
scar tissue blocks access to distal stump
neuroma developement
degrees of nerve injury
crush injury (epineurium intact) complete splitting
surgical method of nerve repair
sow together the epineurium
what can occur following a nerve injury
development of neuropathic pain
what can occur at nerve injury sites
spontaneous activity
burst of electrical impulses to CNS
what mechanisms are involved in spontaneous activity
neuropeptides
sodium channels
TRP channels
Inflammatory mediators
what is wallerian degeneration
myelin sheath pulls away from segment
axon breaks into smaller segments
death of segment
