A voltage-gated channel is a type of protein found in the cell membrane that opens or closes in response to changes in electrical voltage across the membrane. These channels are crucial for the generation and propagation of electrical signals in cells, particularly in neurons and muscle cells. When the membrane potential reaches a certain threshold, the channel opens, allowing ions like sodium or potassium to flow in or out of the cell. This movement of ions creates an electrical current, which can trigger various cellular processes. Voltage-gated channels play a key role in actions such as action potentials in neurons, which are essential for communication within the nervous system. Their precise functioning is vital for muscle contraction and other physiological processes.