Question

What happens to the acetylcholine after it diffuses away from its receptor on the motor end plate?

A. It is reabsorbed by the axon terminal.
B. It is broken down by enzymes in the synaptic cleft.
C. It triggers the release of calcium ions.
D. It initiates the action potential.

Answer 1

Following its function, acetylcholine is broken down by the enzyme acetylcholinesterase in the synaptic cleft.

Step-by-step explanation:

After acetylcholine (ACh) diffuses away from its receptor on the motor end plate, it is broken down by enzymes in the synaptic cleft. The specific enzyme that breaks down ACh is called acetylcholinesterase (AChE). Acetylcholinesterase resides in the synaptic cleft and degrades ACh into acetyl and choline, preventing it from remaining bound to the receptors on the muscle cell, which would lead to a prolonged muscle contraction.