The muscular system facilitates movement through contraction, which acts upon bones, which act as levers, and so forth. The muscular system is controlled by the nervous system, although some muscles (such as the cardiac muscle) can be completely autonomous. There are three distinct types of muscles: skeletal muscles, cardiac muscles, and smooth muscles.
Skeletal muscle is a type of striated muscle, is multinucleated, and are usually attached to tendons that connect them to bone. Skeletal muscles generally contract voluntarily (via somatic nerve stimulation), although they can contract involuntarily through reflexes or through autonomic nerve stimulation. The whole muscle is wrapped in a special type of connective tissue called epimysium.