Which of the following phases follows depolarization in an action potential?

Following depolarization in an action potential, the next phase is repolarization. During depolarization, the membrane potential of the neuron becomes more positive due to the influx of sodium ions (Na+) through voltage-gated sodium channels. Once the membrane reaches its peak depolarization, these sodium channels begin to close, and voltage-gated potassium channels open.

In the repolarization phase, potassium ions (K+) exit the neuron, causing the membrane potential to decrease back toward the resting membrane potential. The efflux of potassium counteracts the previous influx of sodium, leading to a return to a more negative membrane potential.

This transition is essential for resetting the neuronal membrane and preparing it for the next potential action potential, following the all-or-nothing principle. The repolarization is critical in ensuring that the neuron can fire in a single direction and maintain a proper signal transmission in response to stimuli.