Sarcomere is a highly organized structure found in striated muscles. It is made up of muscle fibers or myofibrils of varying lengths organized in a stacked pattern with the myofibrils running parallel to each other. There are two types of myofibrils – the thick myosin filament and the thin actin filament. The myosin and actin strands overlap each other in an alternating arrangement, giving skeletal and cardiac muscles their characteristic striated appearance.