Answer – A sarcomere is the most basic contractile unit of a striated muscle.
Explanation:
The human body is composed primarily of striated and unstriated muscles. Striated muscles include the voluntary skeletal muscles and the involuntary cardiac muscles. Unstriated muscles, on the other hand, comprise only the involuntary smooth muscles.
Striated muscles are identifiable by their distinct physical appearance. They are long muscle fibers with alternating dark and light bands, or striations, visible under the microscope.
These striations appear due to the alternation of specific protein filaments – actin and myosin – in what are known as sarcomeres. A sarcomere is the fundamental contractile unit of striated muscles that repeats to make up the tubular myofibrils of muscle tissue.
According to the sliding filament theory, the force resulting from actin (thin) protein filaments sliding past myosin (thick) protein filaments causes the corresponding sarcomere to contract. This movement in combination with muscular relaxation contributes to various muscle functions in the human body.
