ANATOMY

Detailed explanation-1: -The Z disc is where the actin filaments attach to and thereby serves as the anchoring point of actin filaments in a sarcomere.

Detailed explanation-2: -Z-discs (Z-disk, Z-line, Z-band) delineate the lateral borders of sarcomeres and are the smallest functional units in striated muscle.

Detailed explanation-3: -In electron micrographs of cross-striated muscle, the Z-line (from the German “zwischen” meaning between) appears in between the I-bands as a dark line that anchors the actin myofilaments. Surrounding the Z-line is the region of the I-band (for isotropic).

Detailed explanation-4: -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.