MICROANATOMY

Detailed explanation-1: -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-2: -According to sliding filament theory of muscle contraction, the actin and myosin filament slide past each other with the help of cross bridge to reduce the length of the sarcomeres. The smallest unit of muscle contraction is a sarcomere(which is delineated by Z-lines).

Detailed explanation-3: -The sarcomere is the smallest contractile unit in the myofibril. Sarcomeres contract because the Z-lines move closer together. As the sarcomeres contract the myofibrils contract. As the myofibrils contract the muscle cell contracts.

Detailed explanation-4: -A sarcomere is the functional unit (contractile unit) of a muscle fiber. As illustrated in Figure 2-5, each sarcomere contains two types of myofilaments: thick filaments, composed primarily of the contractile protein myosin, and thin filaments, composed primarily of the contractile protein actin.