MUSCLE PHYSIOLOGY

Detailed explanation-1: -Each bundle of muscle fiber is called a fasciculus and is surrounded by a layer of connective tissue called the perimysium.

Detailed explanation-2: -The myofibrils are made up of thick and thin myofilaments, which give the muscle its striped appearance. The thick filaments are composed strands of the protein myosin, and the thin filaments are strands of the protein actin, along with two other muscle regulatory proteins, tropomyosin and troponin.

Detailed explanation-3: -Approximately 20–80 of these muscle fibers are grouped together in a parallel arrangement called a muscle fascicle or fiber bundle that is encapsulated by a perimysium, which is thicker than the epimysium enclosing each of the bundled muscle fibers.