Excitation-contraction coupling in myocardium relies on sarcolemma depolarization and subsequent Ca2+ entry  to trigger Ca2+ release from the sarcoplasmic reticulum. When an action potential depolarizes the cell membrane, voltage-gated Ca2+ channels (e.g., L-type calcium channels) are activated.
Excitation-contraction coupling in myocardium relies on sarcolemma depolarization and subsequent Ca2+ entry to trigger Ca2+ release from the sarcoplasmic reticulum. When an action potential depolarizes the cell membrane, voltage-gated calcium channels (e.g., L-type calcium channels) are activated.