MUSCLE PHYSIOLOGY

Detailed explanation-1: -If present, calcium ions bind to troponin, causing conformational changes in troponin that allow tropomyosin to move away from the myosin binding sites on actin.

Detailed explanation-2: -The molecular regulation of striated muscle contraction couples the binding and dissociation of Ca2+ on troponin to the movement of tropomyosin on actin filaments. In turn, this process exposes or blocks myosin binding sites on actin, thereby controlling myosin crossbridge dynamics and consequently muscle contraction.

Detailed explanation-3: -Tropomyosin binds actin filaments and covers the myosin binding sites. Troponin interacts with tropomyosin. When stimulated by calcium, troponin undergoes a conformational change that moves the tropomyosin and exposes the myosin binding sites on the actin protein.