MUSCLE PHYSIOLOGY

Detailed explanation-1: -Thin filaments are composed primarily of the contractile protein actin. As illustrated in Figures 2-8, A and B, actin is composed of small globular subunits (G actin) that form long strands called fibrous actin (F actin).

Detailed explanation-2: -Thin filaments are polarized copolymers of actin subunits complexed with troponin-tropomyosin regulatory units and stabilized at their ends by specialized actin-capping proteins (Figure 1).