CVS Practice Test

What is the term for the sudden depolarization and subsequent repolarization of the cell membrane potential?

1. Resting membrane potential

2. Repolarization potential

3. Action potential

4. Ion potential

The correct answer is: Action potential

The term that describes the sudden depolarization and subsequent repolarization of the cell membrane potential is known as an action potential. This phenomenon is crucial in the functioning of neurons and muscle cells. During an action potential, the cell membrane undergoes rapid changes in electrical charge: it first depolarizes when sodium channels open, allowing sodium ions to flow into the cell, which temporarily reverses the membrane potential. This is followed by repolarization, during which potassium channels open, allowing potassium ions to flow out of the cell, restoring the negative resting membrane potential. Understanding action potentials is vital because they are fundamental to the transmission of signals in the nervous system and muscle contractions. Other options, while related to membrane potentials, do not accurately describe this specific rapid sequence of events. For instance, resting membrane potential refers to the electrical state of the cell when it is not actively transmitting a signal, and repolarization potential is merely a part of the action potential process rather than the whole event. Ion potential is not a standardized term in the context of cell membrane physiology.