Zellmembranpotenzials

Zellmembranpotenzial refers to the electrical potential difference across the plasma membrane of a cell. This potential arises from the unequal distribution of ions inside and outside the cell. The cell membrane is selectively permeable, allowing some ions to pass through more easily than others, primarily through ion channels and pumps. Key ions involved in establishing and maintaining the membrane potential include sodium (Na+), potassium (K+), chloride (Cl-), and calcium (Ca2+).

The resting membrane potential is the electrical potential of a cell when it is not actively stimulated. It is typically negative inside the cell relative to the outside, due to the outward movement of positive ions like potassium and the inward movement of negative ions like chloride, as well as the action of the sodium-potassium pump which actively transports ions against their concentration gradients.

Changes in the cell membrane potential are crucial for cell function, particularly in excitable cells like neurons and muscle cells. These changes can occur due to the opening or closing of ion channels in response to stimuli. Depolarization occurs when the membrane potential becomes less negative, often due to the influx of positive ions. Repolarization is the return of the membrane potential to its resting state. Hyperpolarization is when the membrane potential becomes more negative than the resting potential. These electrical signals are fundamental to processes like nerve impulse transmission and muscle contraction.