What is the primary event that occurs during repolarization?

During the process of repolarization in a neuron, the primary event is the diffusion of K+ ions out of the cell. After the depolarization phase, which involves the influx of Na+ ions into the neuron through voltage-gated sodium channels, the inside of the cell becomes more positively charged compared to the outside. To restore the resting membrane potential, the cell needs to return to a more negative internal environment.

Repolarization primarily occurs through the opening of voltage-gated potassium channels, allowing K+ ions, which are more concentrated inside the cell, to flow out. This efflux of positive charge helps to bring the membrane potential back down, returning it toward the resting state. As K+ ions exit the cell, the interior becomes less positive and approaches the original resting membrane potential.

This event is crucial for the proper functioning of neurons and the generation of action potentials. It contributes to the overall excitability and communication between neurons, making it a key aspect of cellular signaling in the nervous system.