When an axon releases a transmitter at the nerve-muscle junction, the response of the muscle is to:
A) always relax.
B) always contract.
C) relax or contract, depending on the transmitter.
D) relax or contract, depending on the duration and amount of transmitter.

Question

Quizplus · Accepted Answer

When an axon releases a transmitter at the nerve-muscle junction, the response of the muscle is to always contract. This is known as the "all-or-nothing" principle of muscle contraction, where the muscle fiber either contracts fully or not at all in response to the neurotransmitter acetylcholine released by the axon.

When an Axon Releases a Transmitter at the Nerve-Muscle Junction