MICROANATOMY

Detailed explanation-1: -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-2: -Myofibrils are composed of long proteins including actin, myosin, and titin, and other proteins that hold them together. These proteins are organized into thick, thin, and elastic myofilaments, which repeat along the length of the myofibril in sections or units of contraction called sarcomeres.

Detailed explanation-3: -Muscles are composed of myofibrils containing the myofilaments actin and myosin. Under the influence of adenosine triphosphate (ATP), actin and myosin form a contractile compound, actomyosin, which is required for muscle contraction.

Detailed explanation-4: -The actin to myosin filament ratio varies from 3 to 4 within each individual myofibril. The described variability of the actin filaments arrays leads to several difficulties in an explanation of the mechanism of muscular contraction.

Detailed explanation-5: -A sarcomere is the basic contractile unit of muscle fiber. Each sarcomere is composed of two main protein filaments-actin and myosin-which are the active structures responsible for muscular contraction.