ANATOMY

Detailed explanation-1: -The globular heads of myosin bind actin, forming cross-bridges between the thick and thin filaments. It is important to note that the orientation of myosin molecules in the thick filaments reverses at the M line of the sarcomere.

Detailed explanation-2: -Cross-bridge theory states that actin and myosin form a protein complex (classically called actomyosin) by attachment of myosin head on the actin filament, thereby forming a sort of cross-bridge between the two filaments.

Detailed explanation-3: -The movements of myosin appear to be a kind of molecular dance. The myosin reaches forward, binds to actin, contracts, releases actin, and then reaches forward again to bind actin in a new cycle. This process is known as myosin-actin cycling.

Detailed explanation-4: -cross·bridge ˈkrȯs-ˌbrij. : the globular head of a myosin molecule that projects from a myosin filament in muscle and in the sliding filament hypothesis of muscle contraction is held to attach temporarily to an adjacent actin filament and draw it into the A band of a sarcomere between the myosin filaments.

Detailed explanation-5: -The crossbridge cycle describes the calcium-dependent interaction of actin and myosin during muscle contraction. Intracellular calcium binds troponin and causes a conformational change, leading to the movement of tropomyosin out of the myosin-binding site on actin.