Question

The rising phase of the action potential is due to

A) Na+ flow into the cell only.
B) Na+ flow out of the cell only.
C) K+ flow out of the cell only.
D) K+ flow into the cell only.
E) Na+ flow out of the cell and K+ flow into the cell.

Answer 1

The rising phase of the action potential is due to the flow of sodium ions (Na+) into the cell, which causes depolarization.

Step-by-step explanation:

The rising phase of the action potential is due to the flow of sodium ions (Na+) into the cell. When a nerve impulse is generated, sodium channels open, allowing sodium ions to enter the cell and causing depolarization, which is the rising phase of the action potential. This depolarization reverses the charge across the membrane, making the inside of the cell more positive than the outside.