ANATOMY

Detailed explanation-1: -The sarcomere is the fundamental unit of contraction and is defined as the region between two Z-lines. Each sarcomere consists of a central A-band (thick filaments) and two halves of the I-band (thin filaments ). The I-band from two adjacent sarcomeres meets at the Z-line.

Detailed explanation-2: -A sarcomere is defined as the segment between two neighboring Z-discs and is composed of long, fibrous proteins such as myosin and actin [7].

Detailed explanation-3: -A sarcomere is defined as the distance between the Z-lines. The Z-lines are pulled closer together during contraction and move further apart during relaxation. The Z-lines are closer during contraction because actin and myosin interaction generates cross-bridges, which slide the myofilaments over each other.

Detailed explanation-4: -Z line. noun. : any of the dark bands across a striated muscle fiber that mark the junction of actin filaments in adjacent sarcomeres.

Detailed explanation-5: -The vertical lines within the I band, one of which has been labeled here with the letter W, represent a region called the Z line. The Z lines usually appear slightly darker in micrographs as there are other protein filaments present here in addition to actin. Two successive Z lines mark the boundary of each sarcomere.