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