What is depolarization?

As a subject matter expert in the field of cellular physiology, I can provide you with a detailed explanation of depolarization. Depolarization refers to the process by which the resting membrane potential of a cell, particularly a muscle or nerve cell, becomes less negative. This occurs when there is a change in the cell membrane's permeability to ions, particularly sodium (Na+). Under normal resting conditions, the inside of a cell is more negatively charged than the outside due to the difference in ion concentrations across the cell membrane. This is known as the resting membrane potential. During depolarization, the cell membrane becomes more permeable to sodium ions, which are more concentrated outside the cell. Sodium ions then rush into the cell, causing the inside to become less negative (or more positive) relative to the outside. This influx of positive charge reduces the difference in charge between the inside and outside of the cell, which is referred to as the loss of polarization. This process is crucial for the initiation and propagation of action potentials in neurons and muscle cells, which are the electrical signals that allow these cells to communicate and contract, respectively.

medical Definition of depolarization. : loss of polarization; especially : loss of the difference in charge between the inside and outside of the plasma membrane of a muscle or nerve cell due to a change in permeability and migration of sodium ions to the interior.