GENERAL HISTOLOGY

Detailed explanation-1: -A bands (or anisotropic bands): It is also called the dark band and contains the whole thick filament (myosin). I bands (or isotropic bands): it is called the light band that contains only the thin filament (actin). The thin filament lies between the two thick filaments.

Detailed explanation-2: -The Z disk (or Z line) defines the boundaries of a muscle sarcomere. Two adjacent Z disks along the myofibril mark the boundaries of a single sarcomere. The Z disks are the attachment sites for the thin filaments. Therefore, from each Z disk, thin filaments extend to two neighboring sarcomeres.

Detailed explanation-3: -Z-discs (Z-disk, Z-line, Z-band) delineate the lateral borders of sarcomeres and are the smallest functional units in striated muscle. The core of a Z-disc consists of actin filaments coming from adjacent sarcomeres which are crosslinked by actinin molecules [1].