ANATOMY

Detailed explanation-1: -I-band: The area adjacent to the Z-line, where actin is not superimposed by myosin. A-band: The length of a myosin within a sarcomere. M-line: The line at the center of a sarcomere to which myosin bind. Z-line: Neighboring, parallel lines that define a sarcomere.

Detailed explanation-2: -The arrangement of the thick myosin filaments across the myofibrils and the cell causes them to refract light and produce a dark band known as the A Band. In between the A bands is a light area where there are no thick myofilaments, only thin actin filaments. These are called the I Bands.

Detailed explanation-3: -The light bands are called I bands and contain only thin filaments. The dark bands are called A bands and contain thick and thin filaments, with the thick filaments running the entire length of the A band. Thus the length of the thick filament determines the length of the A band.

Detailed explanation-4: -The Z-band (Z-line, Z-disc) defines the boundary of the sarcomere in striated muscle and bisects the I-band of neighbouring sarcomeres (Fig.