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: -Cardiovascular Physiology Troponin T binds the complex to tropomyosin; troponin C binds calcium; and troponin I regulates the interaction of the complex with tropomyosin, binding to troponin C during systole and to actin during diastole.

Detailed explanation-3: -Each heartbeat is triggered by a pulse of intracellular calcium ions which bind to troponin on the actin-containing thin filaments of heart muscle cells, initiating a change in filament structure that allows myosin to bind and generate force.

Detailed explanation-4: -(2) Calcium binds to troponin C, which induces a conformational change in the troponin complex. This causes tropomyosin to move deeper into the actin groove, revealing the myosin-binding sites.

Detailed explanation-5: -Troponin and tropomyosin are two proteins that are present on the thin filaments of the muscle cells and help in the contraction of muscles. However, they have opposite functions. While troponin promotes muscle contraction, tropomyosin blocks muscle contraction.