The following are the steps involved in transmission at a cholinergic synapse. What is the correct sequence for these events?
1) Chemically-gated sodium channels on the postsynaptic membrane are activated.
2) Calcium ions enter the synaptic terminal.
3) Acetylcholinesterase hydrolyzes acetylcholine.
4) An action potential depolarizes the synaptic terminal at the presynaptic membrane.
5) The pre-synaptic terminal reabsorbs choline.
6) Acetylcholine is released from storage vesicles by exocytosis.
7) Acetylcholine binds to receptors on the postsynaptic membrane.
8) Calcium ions are removed from the cytoplasm of the pre- synaptic terminal.
A) 4, 2, 6, 7, 8, 5, 3, 1
B) 4, 2, 6, 7, 1, 8, 3, 5
C) 2, 4, 6, 7, 1, 8, 3, 5
D) 2, 5, 4, 6, 7, 1, 8, 3
E) 6, 4, 2, 7, 1, 8, 3, 5

Question

Quizplus · Accepted Answer

The correct sequence of events for transmission at a cholinergic synapse is as follows:
1) An action potential depolarizes the synaptic terminal at presynaptic membrane (4).
2) Calcium ions enter the synaptic terminal (2).
3) Acetylcholine is released from storage vesicles by exocytosis (6).
4) Acetylcholine binds to receptors on the postsynaptic membrane (7).
5) Chemically-gated sodium channels on the postsynaptic membrane are activated (1).
6) Calcium ions are removed from the cytoplasm of the presynaptic terminal (8).
7) Acetylcholinesterase hydrolyzes acetylcholine (3).
8) The presynaptic terminal reabsorbs choline (5).

Therefore, the correct sequence is 4, 2, 6, 7, 1, 8, 3, 5, which corresponds to choice B.

The Following Are the Steps Involved in Transmission at a Cholinergic