A sodium channel is a type of protein found in the cell membranes of neurons and muscle cells. It plays a crucial role in the generation and propagation of electrical signals, known as action potentials. When a nerve cell is stimulated, sodium channels open, allowing sodium ions to flow into the cell. This influx of positive charge causes the cell to become more positively charged, leading to the rapid transmission of signals along the nerve. These channels are essential for various physiological processes, including muscle contraction and the transmission of pain signals. Dysfunction in sodium channels can lead to medical conditions such as epilepsy or cardiac arrhythmias. Understanding sodium channels is vital for developing treatments for these disorders.