Zellpotenziale

Zellpotenziale refers to the electrical potential difference across the plasma membrane of a cell. This potential difference arises from the uneven distribution of ions, primarily sodium (Na+), potassium (K+), chloride (Cl-), and calcium (Ca2+), across the cell membrane. The cell membrane is selectively permeable, allowing some ions to pass through more easily than others, often via ion channels.

At rest, most cells maintain a resting membrane potential, which is typically negative on the inside relative to the outside. This is largely due to the action of the sodium-potassium pump, which actively transports sodium ions out of the cell and potassium ions into the cell, creating concentration gradients. Furthermore, potassium ions are generally more permeable across the membrane at rest than sodium ions, contributing to the negative charge inside.

Changes in Zellpotenziale are crucial for cellular function, particularly in excitable cells like neurons and muscle cells. When a cell is stimulated, ion channels open or close, leading to rapid changes in ion permeability and thus altering the membrane potential. These changes can result in depolarization, where the membrane potential becomes less negative, or hyperpolarization, where it becomes more negative. Action potentials, rapid and transient changes in membrane potential, are fundamental to nerve impulse transmission and muscle contraction. Even in non-excitable cells, Zellpotenziale play roles in various processes like nutrient transport and cell signaling.