Meet Your Skeleton: The Bones That Hold You Up

Right now, inside your body, you are holding up 206 bones! Without them, you would be as floppy as a beanbag. Bones are hard, but they are alive, and they are growing bigger every single day, just like you.

Name three bones in your body. Explain why bones need muscles to move. Find the longest bone in your leg. Describe one way to keep bones strong.

Babies are born with about 300 bones. As you grow, some of those bones join together, so grown-ups end up with 206 bones. Your skull is a hard bowl that protects your brain. Your ribs curve around your chest like a cage to protect your heart and lungs. Your backbone, called the spine, is not one long bone -- it is 33 small bones called vertebrae, stacked up like blocks.

Bones cannot move by themselves. Muscles are attached to your bones, and they pull on them like ropes. When you bend your elbow, a muscle called your biceps pulls your lower arm bone up. When you straighten it back out, a muscle called your triceps pulls it back down.

Bones need calcium to stay strong, and calcium is found in foods like milk, cheese, and yogurt. Bones also get stronger when you move -- running, jumping, and climbing all help. And wearing a helmet when you ride a bike protects your skull, the bone that guards your brain.