Question

question 17
mark this question
which event predominantly dictates the repolarization phase of an action potential in neurons?
voltage - gated potassium (k⁺) channel opening
voltage - gated sodium (na⁺) channel inactivation
voltage - gated sodium (na⁺) channel opening
voltage - gated (k⁺) channel inactivation

Explanation:

During the repolarization phase of an action potential in neurons, voltage - gated potassium (\(K^{+}\)) channels open. This allows \(K^{+}\) ions to flow out of the neuron. The outflow of positively - charged \(K^{+}\) ions helps to restore the negative resting membrane potential, which is the essence of repolarization. Voltage - gated sodium (\(Na^{+}\)) channel inactivation occurs during the falling phase of the action potential but is more related to stopping the influx of \(Na^{+}\) (which was responsible for depolarization) rather than directly dictating repolarization. Voltage - gated sodium (\(Na^{+}\)) channel opening is the main event in depolarization. Voltage - gated (\(K^{+}\)) channel inactivation would prevent \(K^{+}\) efflux, which is contrary to what is needed for repolarization.

Answer:

Voltage - Gated Potassium (\(K^{+}\)) Channel Opening