Question

The rising phase of the action potential is due to

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

Answer 1

The rising phase of the action potential is due to the flow of Na+ ions into the cell and K+ ions out of the cell.

Step-by-step explanation:

The rising phase of the action potential is due to the flow of Na+ ions into the cell and K+ ions out of the cell.

At the resting potential, there is a higher concentration of Na+ ions outside the cell and K+ ions inside the cell.

When a nerve impulse occurs, Na+ channels open, allowing Na+ ions to enter the cell.

This depolarizes the membrane and results in the rising phase of the action potential.

At the peak of the action potential, K+ channels open, allowing K+ ions to leave the cell, leading to repolarization and the eventual restoration of the resting potential.