MUSCLE PHYSIOLOGY

Detailed explanation-1: -The Z-band (Z-line, Z-disc) defines the boundary of the sarcomere in striated muscle and bisects the I-band of neighbouring sarcomeres (Fig. 1a) [1].

Detailed explanation-2: -A sarcomere is the region from one Z line to the next Z line. Many sarcomeres are present in a myofibril, resulting in the striation pattern characteristic of skeletal muscle. Myofibrils are composed of smaller structures called myofilaments.

Detailed explanation-3: -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.