Which of the following actions is associated with the opening of K+ channels during an action potential?

Which of the following actions is associated with the opening of K+ channels during an action potential?

• A. Repolarization of the membrane
• B. Depolarization of the membrane
• C. Maintaining resting membrane potential
• D. Initiation of the action potential

Answer: (A)

The opening of potassium (K+) channels during an action potential primarily facilitates the repolarization of the membrane. During the action potential, there is a rapid influx of sodium (Na+) ions through voltage-gated Na+ channels, leading to depolarization, where the inside of the cell becomes more positive relative to the outside. Once the depolarization reaches a peak, the voltage-gated Na+ channels close, and voltage-gated K+ channels open. As K+ channels open, potassium ions begin to flow out of the cell, driven by both the concentration gradient and the electrical gradient, as the inside of the cell is more positive. The efflux of K+ ions causes the membrane potential to move back toward the resting state, which is more negative. This process is what constitutes repolarization, returning the membrane potential to a level closer to the resting membrane potential. Therefore, the association of K+ channel opening with the repolarization phase is a critical aspect of the action potential process, as it restores the resting membrane potential and allows the neuron to be ready for subsequent action potentials.

The opening of potassium (K+) channels during an action potential primarily facilitates the repolarization of the membrane. During the action potential, there is a rapid influx of sodium (Na+) ions through voltage-gated Na+ channels, leading to depolarization, where the inside of the cell becomes more positive relative to the outside. Once the depolarization reaches a peak, the voltage-gated Na+ channels close, and voltage-gated K+ channels open.

As K+ channels open, potassium ions begin to flow out of the cell, driven by both the concentration gradient and the electrical gradient, as the inside of the cell is more positive. The efflux of K+ ions causes the membrane potential to move back toward the resting state, which is more negative. This process is what constitutes repolarization, returning the membrane potential to a level closer to the resting membrane potential.

Therefore, the association of K+ channel opening with the repolarization phase is a critical aspect of the action potential process, as it restores the resting membrane potential and allows the neuron to be ready for subsequent action potentials.