MUSCLE PHYSIOLOGY

Detailed explanation-1: -Sarcomeres are highly stereotyped and are repeated throughout muscle cells, and the proteins within them can change in length, which causes the overall length of a muscle to change. An individual sarcomere contains many parallel actin (thin) and myosin (thick) filaments.

Detailed explanation-2: -A sarcomere is the basic contractile unit of a myocyte (muscle fibre). A sarcomere is composed of two main protein filaments (thin actin and thick myosin filaments) which are the active structures responsible for muscular contraction.

Detailed explanation-3: -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-4: -Each sarcomere is composed of protein filaments (myofilaments) that include mainly the thick filaments called myosin, and thin filaments called actin.