Na+ channels are specialized proteins found in the cell membranes of neurons and muscle cells. They allow the passage of sodium ions (Na+) into the cell, which is crucial for generating electrical signals. When a cell is stimulated, these channels open, leading to a rapid influx of sodium ions, causing depolarization of the cell membrane. The opening and closing of Na+ channels are essential for processes like action potentials in neurons, which transmit signals throughout the nervous system. Dysfunction in these channels can lead to various medical conditions, including epilepsy and cardiac arrhythmias.