When can a second action potential travel along an axon?

Question

This is a practice-test question for my A&P class:

A second action potential cannot travel along an axon until:
A. the resting potential has been reestablished.
B. sodium ions have been pumped out of the axon.
C. potassium ions have been pumped into the axon.
D. proteins have been resynthesized.
E. all of the above.

Please explain why it is not E.

Answer 1

A. It is not E bec for an action potential to travel it is required that the ions on the ECF & the ICF are back to its resting state which does not involve the protein synthesis. Also a second action potential cantravel soon after the absolute refractory period i.e., during the relative refractory period if a strong stimulus is applied. I am not sure but i think the rel. ref. Pd. is after one third of the relaxation is over.

Answer 2

I will explain the first one - The magnitude of the change of the membrane potential in a graded potential is dependent upon the strength of the stimulus. The larger stimulus, the greater change in potential. Graded potentials are not the nerve signals that travel along an axon, but do influence their generation. If depolarization occurs, then voltage-gated ion channels open and develop an action potential. Actions potentials are the nerve impulses that occur when the membrane voltage reaches a certain value, known as the threshold. Action potentials are considered an "all-or-nothing" phenomenon, there is no variance in their strength - it either occurs, or does not.

Answer 3

A