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.
Step 2. Depolarization; Na+ Channels Open. During the depolarization phase of the action potential, open Na+ channels allow Na+ ions to diffuse into the cell. This inward movement of positive charge makes the membrane potential more positive (less negative).