There are three types of muscle tissue: striated, smooth, and cardiac. Of the three, striated is the one that will be influential in our makeup design. Viewed under a microscope, striated muscle appears to be striped. Striated muscle is also called voluntary muscle since it is under our conscious control. Over 640 voluntary muscles make up 40 to 50 percent of our body weight.[6] Voluntary muscles are grouped and arranged in two or more layers and give the human form its characteristic shape beneath layers of fat and skin.[7]