Question

a&p flix quiz: events at the neuromuscular junction
6 parts | 0.5 of 1 point
part d (4 of 6)
2 tries left
calcium entry into the axon terminal triggers which of the following events?
acetylcholine is released into the cleft by active transporters in the plasma membrane of the axon terminal.
cation channels open and sodium ions enter the axon terminal while potassium ions exit the axon terminal.
acetylcholine binds to its receptor.
synaptic vesicles fuse to the plasma membrane of the axon terminal and release acetylcholine.

Explanation:

When calcium enters the axon terminal, it causes synaptic vesicles containing acetylcholine to fuse with the plasma - membrane of the axon terminal and release acetylcholine into the synaptic cleft. Acetylcholine is not released by active transporters. Cation channels opening for sodium and potassium entry/exit is not directly triggered by calcium entry in this context. Acetylcholine binding to its receptor occurs after its release into the cleft.

Answer:

Synaptic vesicles fuse to the plasma membrane of the axon terminal and release acetylcholine.