The ACh molecules diffuse across the synaptic cleft and bind to the muscle fiber receptors, thereby initiating a muscle contraction. Muscle contraction is initiated with the depolarization of the sarcolemma caused by the sodium ions' entrance through the sodium channels associated with the ACh receptors.

Sodium plays a role in communication between your nervous system and your muscle tissue to control muscle movement. Before a muscle contraction occurs, sodium rushes into your nerve cells, triggering the transmission of a small electrical signal. When your muscles sense this signal, your muscle fibers shorten and contract.

Sodium plays a vital role in our bodies. In partnership with another element, potassium, it acts like a chemical battery that powers our nerve impulses and muscle contractions. This battery is maintained by proteins called sodium-potassium pumps, which are embedded like tunnels in our cell membranes.

Open channels allow an influx of sodium ions into the cytoplasm of the muscle fiber. The sodium influx also sends a message within the muscle fiber to trigger the release of stored calcium ions.