Muscular System

The muscular system is a complex network of tissues that permits movement of the body, maintains posture, and circulates blood throughout the human body. It is comprised of three distinct types of muscles: skeletal, smooth, and cardiac. Skeletal muscles are attached to bones and are under voluntary control, enabling physical actions such as walking, grasping, and speaking. Smooth muscles, found in the walls of internal organs such as the stomach and intestines, are involuntary and control physiological functions like digestion and blood vessel constriction. Cardiac muscle, exclusively found in the heart, contracts rhythmically and involuntarily to pump blood throughout the body.

Each muscle, composed of fibrous muscle tissue, reacts to stimuli and contracts to exert force. These muscles are made up of cells called myocytes, which contain contractile proteins – actin and myosin – that slide past each other to produce a contraction. The coordination of the muscular system with the nervous system allows for precise control of muscle function. The body's metabolic rate increases with the overall muscle mass, emphasizing the role of the muscular system in the regulation of energy balance and body temperature as well.