Question

Increasing the amount of action potentials that arrive at the presynaptic terminal will:

A) Increase the amount of depolarization in the terminal
B) Increase the amount of Ca2+ that enters the presynaptic terminal.
C) Increase the number of vesicles that fuse with the presynaptic membrane
D) Increase the amount of neurotransmitter released.

Answer 1

Increasing amount of action potentials that arrive at pre synaptic terminal will increase the amount of Ca2+ that enters the presynaptic terminal.

Step-by-step explanation:

• Neuromuscular junction is called as the site of signal exchange which occur in step wise manner.
• As action potential reaches the axon terminal, it opens axon terminal through which calcium enters.
• Then fusion takes place between presynaptic membrane that causes release of ACh in synaptic cleft through exocytosis.
• Binding of ACh with postsynaptic receptor cause opening of ion channels which allow the entry of sodium and potassium.
• This flow generates action potential that travels to the myofibril and causes muscle contraction.