GENERAL HISTOLOGY

Detailed explanation-1: -Skeletal and cardiac muscle are referred to as striated muscle because of the visible organization of repeating units of contractile filaments, known as sarcomeres, into cylindrical bundles called myofibrils.

Detailed explanation-2: -By studying sarcomeres, the basic unit controlling changes in muscle length, scientists proposed the sliding filament theory to explain the molecular mechanisms behind muscle contraction. Within the sarcomere, myosin slides along actin to contract the muscle fiber in a process that requires ATP.

Detailed explanation-3: -The sarcomere consists of a bundle of myosin-containing thick filaments flanked and interdigitated with bundles of actin-containing thin filaments (Fig. 1). The striated appearance of muscle results from the alternation of thick-filament-containing (A-Band) and thin-filament-containing (I-band) regions.