MEDICAL PHYSIOLOGY

Detailed explanation-1: -This review discusses the role of myosin, a main component of the thick filament, in thick filament formation and the dynamics of myosin in skeletal muscle cells. Changes in the number of myofibrils in myofibers can cause muscle hypertrophy or atrophy.

Detailed explanation-2: -In striated muscle cells, myosin forms the backbone of the thick filaments, which are anchored within the M-band and extend bidirectionally toward the two opposite ends of the sarcomere (171, 247).

Detailed explanation-3: -The thick filaments are composed of myosin, and the thin filaments are predominantly actin, along with two other muscle proteins, tropomyosin and troponin.

Detailed explanation-4: -Most of the cytoplasm consists of myofibrils, which are cylindrical bundles of two types of filaments: thick filaments of myosin (about 15 nm in diameter) and thin filaments of actin (about 7 nm in diameter).

Detailed explanation-5: -Myofibrils are composed of long proteins including actin, myosin, and titin, and other proteins that hold them together.