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The humans move by a system of cells
called muscles. There are three types of muscle (cardiac, smooth, skeletal).
Cardiac muscle is found only in the heart. It is striated and involuntary. Smooth muscle is found in inner organs. It is nonstriated and involuntary. Skeletal muscle is found connected to bones by tendons. It is striated and voluntary. It is organized by pairs that relax and contract to move joints. This muscle is made of fascicles bound by epimysium. Fascicles are made of muscle fibers. Muscle fibers are made of myofybrils. Myofibrils are made by myofilaments. Myofilaments are made of actin and myosin. The organization of these proteins make dark bands (where they overlap) and light bands (where they don't). If they overlap more, then the muscle contracts. The less they overlap the muscle relaxes. |