muscular system

The system in the body composed of muscle cells and tissues that brings about movement of an organ or body part. There are three kinds of muscle: skeletal muscle, which is attached to bones and allows the voluntary movement of limbs; smooth muscle, which is found in internal organs and aids in the involuntary movements that occur in the circulatory, digestive, excretory, reproductive, and respiratory systems; and cardiac muscle, which forms the powerful walls of the heart.)