The muscular system consists of muscle cells and tissues that control movement throughout the body. There are three main types of muscle - skeletal, smooth, and cardiac. Skeletal muscle is voluntary muscle that moves bones and maintains posture. Smooth muscle is involuntary muscle that lines organs and controls functions like digestion. Cardiac muscle is only found in the heart and pumps blood throughout the body under control of the nervous and endocrine systems. The muscular system works with other systems to enable functions essential for survival like mobility, respiration, circulation, and temperature regulation.