GENERAL HISTOLOGY

Detailed explanation-1: -Tropomyosin is a fibrous protein that binds lengthwise along the groove of actin filaments . In striated muscle, each tropomyosin molecule is bound to troponin, which is a complex of three polypeptides: troponin C (Ca2+-binding), troponin I (inhibitory), and troponin T (tropomyosin-binding).

Detailed explanation-2: -The thin filaments consist of globular actin molecules in two long chains wound around each other and each actin molecule has a binding site for myosin. The protein tropomyosin winds around the thin filaments and covers the myosin binding sites.

Detailed explanation-3: -Actin binding stabilizes tropomyosin (Levitsky et al., 2000).

Detailed explanation-4: -Tropomyosin blocks myosin binding sites on actin molecules, preventing cross-bridge formation and preventing contraction in a muscle without nervous input.