MUSCLE PHYSIOLOGY

Detailed explanation-1: -Troponin plays a central role in the calcium-regulation of muscle contraction: Troponin is the sole calcium-binding component of thin filaments (actin-tropomyosin-troponin complex) of striated muscles. Thin filaments without troponin support contraction irrespective of calcium concentration.

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.