Question

What is the correct order of a signal being transmitted across a neuromuscular junction?

A. End plate potential—neurotransmitter—ion channels—synaptic vesicle

B. Synaptic vesicle—neurotransmitter—ion channels—end plate potential

C. Ion channels—end plate potential—neurotransmitter—synaptic vesicle

D. Synaptic vesicle—end plate potential—neurotransmitter—ion channels

Answer 1

B. Synaptic vesicle—neurotransmitter—ion channels—end plate potential

Step-by-step explanation:

When an impulse reaches the synaptic knob, it stimulates the vesicles to move towards the pre-synaptic membrane releasing the acetylcholine(neurotransmitter). This transmitter substance makes the membrane permeable. The transmitter substance then diffuses across the synaptic cleft to the post-synaptic membrane which then becomes depolarised. Sodium ions from cleft then flow through the post-synaptic membrane into the post-synaptic knob causing an action potential at this point. This action potential is then transmitted as a nerve impulse along the neurone. End-plate potential is a change in electrical potential that is chemically induced at the motor neurone leading to muscle contraction because a nerve impulse has reached the nerve endings.