8 - NMJ Flashcards
1
Q
what occurs when an action potential reaches a pre-synaptic membrane?
A
- depol
- ca voltage gated open
- ca enters due to more outside
- cause vesicle fusement
- ach released
2
Q
what causes vesicle to fuse with pre synaptic membranes?
A
- ca entry
- synaptotagmins sense ca
- bind with ca and cause confom change
3
Q
what does ACH bind to?
A
nicotinic receptors [ionotropic ion channel]
4
Q
in NMJ, describe the structure of the post synaptic membrane?
A
- called motor end plate
- junctional folds [sfa]
- many nACH channles
- many Na channels
5
Q
how does Ach binding cause End Plate Potential EPP?
A
- ach binds to nAch
- Na and K channels open
- Na influx higher than K efflux
- resting Em of muscles = -70mv
- epp = -20mv [if bigger than threshold = AP]
6
Q
fate of ACH?
A
acetylcholinesterase
choline + acetate
7
Q
what is myesethnia gravis?
A
- less nACHr @ synpase
- muscle weakness
- treatment = ACHEsterase inhibitors
