MUSCLE PHYSIOLOGY

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: -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-3: -The myofibrils are bundles of interconnected protein filaments of striated muscles. The filaments (myofilaments) included in the myofibrils are mainly thick filaments (myosin), and thin filaments (actin).