Question

a&p flix activity: events at the neuromuscular junction
2 parts | 0.5 of 1 point

termination of neural transmission

which of the following is/are mechanism(s) to end neural transmission at the neuromuscular junction?

select all the correct answers.

ach diffuses away from the synaptic cleft.
ach is taken up by the axon terminal via endocytosis.
ach binds to ach receptors.
ach is broken down into acetic acid and choline by the enzyme acetylcholinesterase (ache).

Explanation:

🆕 New Concept Discovered: Synaptic Transmission Termination
How neurotransmitter signals are turned off

Step 1: Understand the goal of terminating transmission

To stop a muscle from contracting continuously, the signal molecule acetylcholine (ACh) must be removed from the synaptic cleft (the gap between the nerve and the muscle). If ACh remains in the cleft, it will keep binding to receptors and keep the muscle active.

Step 2: Evaluate each mechanism

• ACh diffuses away from the synaptic cleft:
• Yes. Some ACh naturally drifts away out of the gap, meaning it can no longer bind to the muscle receptors. This helps end the signal.
• ACh is taken up by the axon terminal via endocytosis:
• No. While some synapses use reuptake proteins, the neuromuscular junction does not end transmission by directly engulfing whole ACh molecules back into the axon terminal via endocytosis.
• ACh binds to ACh receptors:
• No. Binding to receptors is what starts and continues the transmission, not what ends it.
• ACh is broken down into acetic acid and choline by the enzyme acetylcholinesterase (AChE):
• Yes. This is the primary, highly efficient chemical cleanup crew. AChE rapidly chops ACh into inactive pieces (acetic acid and choline), instantly stopping the signal.

Answer:

• ACh diffuses away from the synaptic cleft.
• ACh is broken down into acetic acid and choline by the enzyme acetylcholinesterase (AChE).