Events at the Neuromuscular Junction Flashcards
0
Q
- Ca+ channels (voltage-gated) open,
A
Ca+ moves into cell
1
Q
- Nerve impulse reaches
A
synaptic end bulbs
2
Q
- Acetylcholine (ACh) released into the
A
synaptic cleft via exocytosis
3
Q
- ACh
A
diffuses across
4
Q
- ACh binds to
A
receptors on motor end plate (muscle)
5
Q
- Na+ channels (ligand-gated) open &
A
Na+ diffuses into the muscle cell (depolarization);
if depolarization passes threshold an action potential is generated
6
Q
- Triggers a muscle
A
action potential along sarcolemma of muscle fiber
7
Q
- ACh is
A
removed from the ligand-gated Na+ channels, which then close
*ACh has to be taken away
8
Q
- The enzyme acetylcholinesterase (attached to postsynaptic membrane) removes
A
ACh from the synaptic cleft by breaking it down into acetic acid & choline
9
Q
- Choline is symported with Na+ into the presynaptic terminal, where it can be
A
recycled to make ACh.
Acetic acid diffuses away from the synaptic cleft.
10
Q
- ACh is reformed within the presynaptic terminal using
A
acetic acid generated from metabolism & choline recycled (from the synaptic cleft)
11
Q
- ACh is then taken up by the
A
synaptic vesicles
