Membrane potential refers to the difference in electric charge across a cell's membrane, primarily due to the distribution of ions like sodium and potassium. This charge difference is crucial for various cellular functions, including the transmission of nerve impulses and muscle contractions. The inside of the cell is typically more negative compared to the outside, creating a resting membrane potential. When a cell is stimulated, the membrane potential can change, leading to depolarization or hyperpolarization. These changes allow for the generation of action potentials, which are essential for communication between neurons and other cells. Understanding membrane potential is fundamental in fields like neuroscience and physiology.