MUSCLE PHYSIOLOGY

Detailed explanation-1: -The I bands contain only thin (actin) filaments, whereas the A bands contain thick (myosin) filaments. The myosin and actin filaments overlap in peripheral regions of the A band, whereas a middle region (called the H zone) contains only myosin.

Detailed explanation-2: -Actin filaments, the thin filaments, are the major component of the I-band and extend into the A-band.

Detailed explanation-3: -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-4: -In physiology, isotropic bands (better known as I bands) are the lighter bands of skeletal muscle cells (a.k.a. muscle fibers). Isotropic bands contain only actin-containing thin filaments.