Triggering of the Muscle Action Potential Occurs After

Question

Triggering of the muscle action potential occurs after
A) acetylcholine binds to chemically-gated channels in the motor end plate.
B) acetylcholinesterase is released from synaptic vesicles into the synaptic cleft.
C) calcium ion binds to channels on the motor end plate.
D) the action potential jumps across the neuromuscular junction.
E) Any of these can produce an action potential in the muscle cell.

Accepted Answer

The muscle action potential is triggered when acetylcholine binds to chemically-gated channels in the motor end plate, causing depolarization of the muscle cell membrane and initiation of an action potential.

Note: option B is incorrect as acetylcholinesterase is an enzyme that breaks down acetylcholine and plays a role in terminating the action potential, but it is not involved in triggering it. Option C is incorrect as calcium ions play a role in the release of acetylcholine from the motor neuron, but they do not directly trigger the muscle action potential. Option D is incorrect as the action potential does not "jump" across the neuromuscular junction, but rather crosses it via diffusion of neurotransmitter molecules. Option E is incorrect as only option A is the correct answer.