Q. What are sarcomeres?
Sarcomeres are the contractile units of the muscle tissue formed of alternating myosin blocks (thick filaments) and actin blocks (thin filaments). Several sarcomeres placed in linear sequence form a myofibril therefore one muscle fiber (cell) has many myofibrils made of sacomeres.
The compartments where myofibrils are inserted and are delimited by an excitable membrane called as sarcolemma, the sarcolemma is the plasma membrane of the muscle cell.