ANATOMY

Detailed explanation-1: -The thick filaments are composed of myosin with the globular heads forming cross-bridges with thin filaments . Myosin-binding proteins, including MyBP-C, are associated with the thick filaments. The giant protein titin extend the length of an entire half sarcomere.

Detailed explanation-2: -The I bands contain only thin (actin) filaments, whereas the A bands contain thick (myosin) filaments. The myosin and actin filaments overlap in peripheral regions of the A band, whereas a middle region (called the H zone) contains only myosin.

Detailed explanation-3: -In addition to myosin that makes up the backbone of the thick filament, four other proteins which are intimately bound to the thick filament, myosin binding protein-C, titin, myomesin, and obscurin play important structural and regulatory roles.

Detailed explanation-4: -An individual sarcomere contains many parallel actin (thin) and myosin (thick) filaments.