Membranpotentialänderungen

Membranpotenzial, also known as membrane potential, refers to the difference in electric potential between the interior and exterior of a biological cell. This electrical potential difference arises from the unequal distribution of ions across the cell membrane. In most cells, this potential is negative on the inside relative to the outside, a state known as the resting membrane potential.

The establishment and maintenance of the membrane potential are primarily due to the selective permeability of the cell membrane to different ions, such as sodium (Na+), potassium (K+), chloride (Cl-), and calcium (Ca2+), and the action of ion pumps, most notably the sodium-potassium pump. This pump actively transports ions against their concentration gradients, contributing to the charge separation across the membrane.

Changes in membrane potential are fundamental to cellular function, particularly in excitable cells like neurons and muscle cells. These changes, such as depolarization (a decrease in the magnitude of the membrane potential) and hyperpolarization (an increase in the magnitude of the membrane potential), can trigger or inhibit cellular responses. For example, in neurons, rapid and transient changes in membrane potential, known as action potentials, are responsible for transmitting nerve impulses. The precise control and dynamic regulation of membrane potential are critical for a wide range of physiological processes.