mechanical, isachaemic, auto-immune, infections, genetic, metabolic, development
1 of 19
What is wallerian degeneration?
Loss of the neuron in front of the axotomic cut. Anterograde degeneration
2 of 19
What is the first thing to happen after axotomy?
Terminal degeneration
3 of 19
What follows terminal degeneration?
Wallerian degeneration
4 of 19
After what does macroglia macrophage infiltrate?
myelin debris
5 of 19
Chromatolysis happens after macroglia infiltrate, what is it?
dissolution of the Nissl bodies in the cell body of a neuron.
6 of 19
What happens after chromatolysis?
retraction of the synaptic terminals, glial cell ensheathement
7 of 19
The last thing to happen in axotomy?
transneuronal degeneration - the one the neuron would have synapsed on degenerates.
8 of 19
What phenomenon can mask the effects of axotomy?
Collateral sprouting
9 of 19
What is a possible mediator for retrograde effects of axotomy?
Lack of neurotrophin
10 of 19
What is a possible mediator for orthograde effects of axotomy?
Lack of factors from the cell body that suppress and inbuild degeneration programme
11 of 19
Biochemical events in the degrading axon?
Ca+ entry, calpain activation, release of FGFs
12 of 19
Biochemical events in the cell body?
Upregulation of c-Jun, Gap-43 and CGRP in motor neurons. Down regulation of Neurofilaments, LNGFR in sensory neurons.
13 of 19
Biochemical events in the schwann cell?
Down-regulation of myelin associated proteins. Upregulation of NCAM, L1, IGFs
14 of 19
Things an axon needs to successful repair in cut axons
Accurate guidance, vigourous regrowth which needs - the cell body to reprogramme protien synthesis for growth, and a local environement that encourages growth
15 of 19
How does the PNS evironment encourage regrowth?
The schwann cells upregulate LI, NCAM, BDNF, NGF, IGFI and 2
16 of 19
What helps accurately guide the axons in regrowth?
The basal lamina tubes, if they stay intact.
17 of 19
What causes protien synthesis in the cell body?
up-regulation of c-Jun, GAP-43, actin and tubulin,
18 of 19
What growth inhibiting factors are present in the CNS?
Proteoglycans (astrocytes) , myelin associated glycoprotiens and NOGO (oligodendrocytes)
19 of 19
Other cards in this set
Card 2
Front
What is wallerian degeneration?
Back
Loss of the neuron in front of the axotomic cut. Anterograde degeneration
Comments
No comments have yet been made