depolarisasi

Depolarisasi, or depolarization, is the process by which a system loses its polarized state or reduces the degree of polarization. The term is used in multiple scientific contexts to describe changes that move a component away from a state of directional order, whether of electrical charges, molecular dipoles, or light waves.

In biology and medicine, depolarization commonly refers to a rapid change in a cell’s membrane potential that makes the inside of the cell less negative relative to the outside. In neurons and muscle cells this is driven by the opening of voltage-gated ion channels, especially sodium channels, which triggers action potentials and, in cardiac tissue, coordinated contraction. After depolarization, repolarization follows to restore the resting potential. Abnormal depolarization patterns can underlie neurological disorders or cardiac arrhythmias; electrical activity is monitored by EEG, EMG, or ECG.

In optics and materials science, depolarization describes a reduction in the degree of polarization of light, caused by scattering, reflection, or propagation through depolarizing media. Depolarizers can convert polarized light into partially or completely unpolarized light, affecting imaging and communication systems. In solid-state physics, depolarization also refers to the loss of spontaneous polarization in ferroelectric or piezoelectric materials when external fields are removed, or to depolarization fields that oppose polarization, with implications for memory devices and sensors.