MUSCLE PHYSIOLOGY

Detailed explanation-1: -I bands are composed of thin actin filaments and proteins that bind actin and they are bisected by the Z line. The thin filaments extend in each direction from the Z-disk, where they do not overlap the thick filaments, they create the light I band.

Detailed explanation-2: -The sarcomeric Z-disk, the anchoring plane of thin (actin) filaments, links titin (also called connectin) and actin filaments from opposing sarcomere halves in a lattice connected by alpha-actinin.

Detailed explanation-3: -The thin filaments are anchored to a big protein complex termed the Z-disc at both ends of the sarcomere. In the center of the sarcomere is the M-line, another giant protein complex, that docks the thick filaments. The Z-disc is part of the I-band region, characterized by the absence of myosin.