Final answer:
The cytoplasm of the neuromuscular synaptic terminal contains vesicles filled with molecules of the neurotransmitter acetylcholine (ACh). Acetylcholine is released by motor neurons and binds to receptors in the motor end plate, triggering depolarization in the muscle cell.
Step-by-step explanation:
The cytoplasm of the neuromuscular synaptic terminal contains vesicles filled with molecules of the neurotransmitter acetylcholine (ACh). Acetylcholine is a neurotransmitter released by motor neurons that binds to receptors in the motor end plate. When an action potential reaches the presynaptic terminal, synaptic vesicles fuse with the membrane and release acetylcholine into the synaptic cleft. The acetylcholine then diffuses across the synaptic cleft and binds to receptors on the postsynaptic membrane, triggering depolarization in the muscle cell.