Repolarisaation

Repolarization is a fundamental process in cell physiology, particularly significant in excitable cells like neurons and muscle cells. It refers to the change in membrane potential that returns a cell to its resting state after depolarization. During depolarization, the cell's interior becomes more positive. Repolarization is the phase where the membrane potential becomes negative again, moving back towards the resting potential.

This process is primarily driven by the movement of ions across the cell membrane. Following depolarization, voltage-gated sodium channels typically inactivate, preventing further influx of positive sodium ions. Simultaneously, voltage-gated potassium channels open, allowing potassium ions to flow out of the cell. This outward movement of positive charge makes the cell's interior more negative, thus achieving repolarization.

The precise timing and characteristics of repolarization are crucial for the proper functioning of excitable tissues. In neurons, repolarization allows the action potential to propagate along the axon and prepares the neuron to fire again. In cardiac muscle, repolarization is essential for the coordinated contraction and relaxation of the heart chambers, enabling the heart to pump blood effectively. Aberrations in repolarization can lead to various pathological conditions, including arrhythmias in the heart.