What is the Role of Calcium Ions in Muscle Contraction?
Calcium ions are essential for muscle contraction. They are released from the sarcoplasmic reticulum in response to a nerve impulse. The calcium ions bind to troponin, causing a conformational change that shifts tropomyosin away from the myosin-binding sites on the actin filaments, thereby allowing cross bridge formation to occur. Without calcium ions, the myosin-binding sites on actin would remain blocked, preventing muscle contraction.