Top Eleven major organ systems are present within animals, although some animals lack one or more of them. The head, or cephalic region, contains four of the five senses as well as a brain encased in the bony skull. These organ systems can be grouped according to their functions. Muscular System allows movement and locomotion. The muscular system produces body movements, body heat, maintains posture, and supports the body.
Muscle fibers are the main cell type.
Action of this system is closely tied to that of the skeletal system. Skeletal System provides support and protection, and attachment points for muscles. The skeletal system provides rigid framework for movement. It supports and protects the body and body parts, produces blood cells, and stores minerals. Skin or Integument is the outermost protective layer.