There are three types of muscle tissue in the human body: skeletal, smooth, and cardiac.
Skeletal striated muscle, or "voluntary muscle", primarily joins to bone with tendons. Skeletal muscle enables movement of the bones of the human skeleton and maintains posture.
Smooth muscle tissue is found in parts of the body where it conveys action without conscious intent. The majority of this type of muscle tissue is found in the digestive and urinary systems where it acts by propelling forward food, chyme, and feces in the former and urine in the latter. Other places smooth muscle can be found are within the uterus, where it helps facilitate birth, and the eye, where the pupillary sphincter controls pupil size.
Cardiac muscle is specific to the heart. It is also involuntary in its movement, and is additionally self-excitatory, contracting without outside stimuli.