What is the Skeletal System?You have a skeleton inside of your body (endoskeleton) made up of bones. Insects and crustaceans have skeletal systems on the outside or their bodies (exoskeletons) that are made of hard plates. Biology4kids.com does a great job illustrating the importance of our skeleton: Your bones or skeletal system gives shape and form to your body, but it also plays other important roles. The main functions of the skeletal system include: • Support—the skeleton supports the b