MUSCLE PHYSIOLOGY

Detailed explanation-1: -For myosin to bind actin, tropomyosin must rotate around the actin filaments to expose the myosin-binding sites.

Detailed explanation-2: -ATP must bind to myosin to break the cross-bridge and enable the myosin to rebind to actin at the next muscle contraction.

Detailed explanation-3: -Calcium is released from the sarcoplasmic reticulum through calcium ion channels when the membrane of the T-tubular system is excited. It binds to Troponin C causing it to conform, hence permitting the myosin head to latch onto the actin filament, onsetting muscle contraction.