Mastering A&P Neurophysiology Practice Test

During the repolarization phase of an action potential, what occurs is that the membrane potential becomes more negative. This phase follows the depolarization, where sodium channels open, allowing sodium ions to flow into the neuron, causing the membrane potential to rise sharply. Once this peak is reached, sodium channels close and potassium channels open. As potassium ions flow out of the neuron, the inside of the cell becomes less positive, moving the membrane potential back towards its resting state. This is the process of repolarization, which effectively restores the negative internal environment of the neuron after depolarization. Thus, during this phase, the membrane potential transitions from a more positive value back toward a more negative state, which is essential for resetting the neuron's ability to generate another action potential.