ANATOMY

Detailed explanation-1: -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-2: -M line-marks the middle of the sarcomere and contains the protein called myomesin. H zone-is the area between the M line and Z disc. The H zone contains only myosin.

Detailed explanation-3: -The middle of the H zone has a vertical line called the M line, at which accessory proteins hold together thick filaments. Both the Z disc and the M line hold myofilaments in place to maintain the structural arrangement and layering of the myofibril.

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.

Detailed explanation-5: -Thin filaments from neighbouring sarcomeres are crosslinked in the Z-disc, and thick filaments within a sarcomere are crosslinked in the M-line. These links hold the filaments in register as the fibres contract, and prevent them coming out of alignment when fibres are stretched.