MICROANATOMY

Detailed explanation-1: -The Z-band (or Z-disk) is a dense fibrous structure made of actin, -actinin, and other proteins. Thin filaments (or actin filament) are anchored at one end at the Z-band. Titin is anchored to both the Z-band and the M-line. Thick filaments are anchored in the middle of the sarcomere at the M-line.

Detailed explanation-2: -Because actin is tethered to structures located at the lateral ends of each sarcomere called z discs or “z bands, ‘’ any shortening of the actin filament length would result in a shortening of the sarcomere and thus the muscle.

Detailed explanation-3: -The z line of the skeletal muscle is the functional end point of the sarcomere and is composed of the protein actin, also known as the thin filament.

Detailed explanation-4: -Z-lines define the boundaries of each sarcomere. The M-line runs down the center of the sarcomere, through the middle of the myosin filaments. The I-band is the region containing only thin filaments. The H-zone contains only thick filaments.