Of those listed, which event occurs first following a depolarising stimulus applied to the presynaptic membrane of an axon terminal?
A) Voltage-gated calcium channels in the membrane open.
B) Synaptic vesicles fuse with the membrane.
C) The postsynaptic cell produces an action potential.
D) Ligand-gated channels open, allowing neurotransmitters to enter the synaptic cleft.

Question

Quizplus · Accepted Answer

Voltage-gated calcium channels open first in response to a depolarizing stimulus applied to the presynaptic membrane of an axon terminal. This allows calcium to enter the axon terminal, which triggers the fusion of synaptic vesicles and the subsequent release of neurotransmitters into the synaptic cleft. The neurotransmitters then bind to ligand-gated channels on the postsynaptic cell, which may produce an action potential.

Of Those Listed, Which Event Occurs First Following a Depolarising