Potenciálváltozás

Potenciálváltozás refers to the change in electrical potential difference across a cell membrane, particularly in biological contexts like neurons and muscle cells. This change is fundamental to how these cells communicate and function. When a stimulus is applied, ion channels in the membrane open or close, altering the flow of ions (like sodium, potassium, and calcium) across the membrane. This movement of charged particles results in a shift in the electrical charge distribution, leading to a change in the membrane potential.

There are two primary types of potential changes: depolarization and hyperpolarization. Depolarization occurs when the membrane potential becomes less negative (or more positive) than the resting potential, often due to the influx of positive ions. This can trigger an action potential if the depolarization reaches a certain threshold. Hyperpolarization, conversely, is when the membrane potential becomes more negative than the resting potential, typically caused by the efflux of positive ions or the influx of negative ions. This makes the cell less likely to fire an action potential. These rapid and transient potential changes are crucial for nerve impulse transmission and muscle contraction.