MUSCLE PHYSIOLOGY

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: -The actin filaments are attached at their plus ends to the Z disc, which includes the crosslinking protein -actinin. The myosin filaments are anchored at the M line in the middle of the sarcomere.

Detailed explanation-3: -A sarcomere is the basic contractile unit of a myocyte (muscle fibre). A sarcomere is composed of two main protein filaments (thin actin and thick myosin filaments) which are the active structures responsible for muscular contraction.

Detailed explanation-4: -The region between two successive Z lines in a myofibril is a contractile unit called a sarcomere.

Detailed explanation-5: -The Z-band (or Z-disk) is a dense fibrous structure made of actin, -actinin, and other proteins. 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.