IstSpannung

IstSpannung, also known as the "resting membrane potential," is a fundamental concept in physiology and neuroscience. It refers to the electrical potential difference across the plasma membrane of a cell when it is at rest, meaning it is not conducting an action potential or being stimulated. This potential is crucial for the proper functioning of excitable cells, such as neurons and muscle cells.

The resting membrane potential is typically around -70 millivolts (mV) in neurons and -90 mV in muscle cells. This negative potential is maintained by the selective permeability of the plasma membrane to different ions. Specifically, the membrane is more permeable to potassium ions (K+) than to sodium ions (Na+), which results in a higher concentration of K+ outside the cell and a higher concentration of Na+ inside the cell.

The maintenance of the resting membrane potential is achieved through the activity of ion channels and pumps. Potassium channels allow K+ to flow out of the cell, contributing to the negative potential. Sodium-potassium pumps actively transport Na+ out of the cell and K+ into the cell, further maintaining the ion concentration gradients.

Changes in the resting membrane potential can significantly impact cellular function. For example, depolarization (a decrease in the membrane potential) can trigger an action potential, which is essential for nerve impulse transmission and muscle contraction. Conversely, hyperpolarization (an increase in the membrane potential) can inhibit cellular activity.

Understanding IstSpannung is essential for comprehending various physiological processes, including neurotransmission, muscle function, and the regulation of cellular excitability.