ANATOMY

Detailed explanation-1: -Sarcomeres. 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.

Detailed explanation-2: -Answer and Explanation: The functional unit of a muscle myofibril is called a sarcomere. The sarcomere is composed of overlapping actin and myosin filaments that form a cross bridge with each other and slide past each other resulting in the shortening of the sarcomere.

Detailed explanation-3: -There can be thousands of sarcomeres within a single muscle cell. 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.

Detailed explanation-4: -The functional unit of myofibril is the sarcomere.

Detailed explanation-5: -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.