What ions enter the muscle cell during action potential generation?

During an action potential in a muscle cell, the depolarization phase is primarily driven by the influx of sodium ions (Na+) into the cell. This occurs when voltage-gated sodium channels in the muscle cell membrane open, allowing Na+ ions to rush into the cell, causing a rapid increase in the membrane potential known as the action potential. Simultaneously, voltage-gated potassium channels in the muscle cell membrane also open, allowing potassium ions (K+) to flow out of the cell. However, the efflux of K+ ions is slower than the influx of Na+ ions, resulting in a net positive charge inside the cell and generating the action potential. The repolarization phase of the action potential occurs as the sodium channels close and the potassium channels remain open, allowing K+ ions to continue flowing out of the cell, restoring the resting membrane potential.