MICROANATOMY

Detailed explanation-1: -Each H-zone is bisected vertically by a dark line called the M-line. Each light I-band has a darker mid line area called the Z-disc. Sarcomere is the functional unit of the skeletal muscle. It is a region of a myofibril between two successive Z-discs.

Detailed explanation-2: -M line: M line contains the protein called myomesin and it marks the centre of the sarcomere. H zone: it is the area between the M line and Z disc and this zone contains only the myosin.

Detailed explanation-3: -Finally, the H-zone is bisected by a dark central line called the M-line (from the German mittel meaning middle).

Detailed explanation-4: -M-line is the attachment site for the thick filaments. It is in the center of the A band. It is present in the center of the sarcomere. During muscle contraction, the thin filaments slide past the thick filaments or M-line.

Detailed explanation-5: -H-band is the zone of the thick filaments that has no actin. Within the H-zone is a thin M-line (from the German “mittel” meaning middle), appears in the middle of the sarcomere formed of cross-connecting elements of the cytoskeleton.