The basic contractile unit of a muscle cell
Muscle is a soft tissue found in most animals. They are responsible for maintaining and changing posture, locomotion. Skeletal muscles are enclosed by a tough layer known as epimysium. Within the epimysium are numerous bundles called fascicles, each of which contains many muscle fibers collectively enclosed by the layer perimysium. These muscle fibres contain muscle cells which are further divided into myofibrils. Myofibrils are complex strands of protein filaments organized together into repeating units called sarcomeres. Hence, a sarcomere is the basic contractile unit of a muscle.