Depolariseerumine

Depolariseerumine refers to the process in which a neuron or muscle cell loses its electrical polarization. Normally, a cell membrane maintains a difference in electrical charge across it, with the inside being negative relative to the outside. This state is called polarization. Depolarisation occurs when positive ions, such as sodium ions (Na+), flow into the cell, making the inside of the cell less negative and closer to zero, or even positive. This influx of positive charge is often triggered by a stimulus, such as a neurotransmitter binding to a receptor on the cell membrane.

This change in membrane potential is a fundamental event in nerve impulse transmission and muscle contraction. If the depolarization reaches a certain threshold level, it can trigger an action potential, which is a rapid and transient reversal of the membrane potential. Following depolarization, a process called repolarisation occurs, where the membrane potential is restored to its resting polarized state. In excitable cells, controlled depolarization and repolarisation are crucial for their function.