Question

to stimulate muscle contraction, acetylcholine is released from the ____________ into the synaptic cleft.

multiple choice
synaptic vesicles
postsynaptic membrane folds
sarcoplasmic reticulum
sarcolemma
terminal cisterns

Explanation:

Acetylcholine is a neurotransmitter. In the neuromuscular junction, synaptic vesicles (located in the axon terminal of the motor neuron) release acetylcholine into the synaptic cleft. The postsynaptic membrane folds (part of the muscle fiber's membrane) have receptors for acetylcholine. The sarcoplasmic reticulum is involved in storing and releasing calcium ions (not acetylcholine). The sarcolemma is the muscle cell membrane. Terminal cisterns are part of the sarcoplasmic reticulum.

Answer:

synaptic vesicles