resting membrane potential

The resting membrane potential is the electrical charge difference across a cell's membrane when the cell is not actively sending a signal. It occurs because the cell maintains a higher concentration of ions (charged particles) outside than inside, mainly sodium and chloride, while potassium ions are more concentrated inside. Special channels and pumps in the membrane regulate this ion distribution, creating a negative charge inside relative to the outside—typically about -70 millivolts. This electrical difference is essential for preparing nerve and muscle cells to quickly respond and transmit signals when needed.