Question

to stimulate muscle contraction, acetylcholine is released from the_______ into synaptic cleft. 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) fuse with the presynaptic membrane and 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 for muscle contraction. The sarcolemma is the muscle cell membrane. Terminal cisterns are part of the sarcoplasmic reticulum.

Answer:

synaptic vesicles