What is meant by membrane potential?

Membrane potential refers to the difference in voltage across a cell membrane, which is primarily established by the distribution of ions and the permeability of the membrane to these ions. In biological systems, this voltage difference is crucial for numerous cellular processes, including the generation of action potentials in neurons, the transport of ions, and the overall regulation of cellular activities.

The membrane potential is created when there are unequal concentrations of ions, such as sodium (Na+), potassium (K+), chloride (Cl-), and calcium (Ca2+), across the membrane. The selective permeability of the membrane allows some ions to pass through more easily than others, leading to a charge separation that creates a voltage difference. This potential is vital for maintaining homeostasis and facilitating communication between cells through signaling processes.

Understanding membrane potential is fundamental in biology, especially in fields such as neurobiology, where the action potential in neurons relies on rapid changes in membrane potential. This concept also plays a role in muscle contraction and the functioning of other excitable cells.