Theoretically, a recognized member of the modern state system possessing formal sovereignty and occupied by a people who see themselves as a single, united nation. Most nations and states aspire to parlance, nation-state is used as a synonym for country or state.
In biology, depolarization is a decrease in the absolute value of a cell's membrane potential. Thus, changes in membrane voltage in which the membrane potential becomes less positive or less negative are both depolarizations.
The action potential has several stages. 1  Depolarization: A stimulus starts the depolarization of the membrane. Depolarization, also referred to as the upswing, is caused when positively charged sodium ions rush into a nerve cell. 2  Repolarization.