Question

Which pump is responsible for initiating muscle contraction through depolarization of muscle cell membrane? 1. Na+ pump. 2. K + pump. 3. Ca2+ pump. 4. Mg2+ pump

Answer 1

Ca2+ pump is responsible for initiating muscle contraction through depolarization of muscle cell membrane. Calcium ions initiate the movement of troponin and tropomyosin on their thin filament called actin filament. This allows the myosin heads to grab and rotate through their path along this thin filament.