Bone up on your skeletal system!

Do you think of your skeleton as a bunch of hard, solid, heavy bones hooked together to give you a shape? The truth is that most of your bones are hollow or spongy inside. They are flexible, which means they can bend at least a little. Your bones have blood vessels, too, as well as nerves, just like all the other parts of your body.

Be thankful for that skeleton of yours! It does three important jobs for you:

1. Support--Your bones hold you up. Without them, you couldn't stand up straight. You'd look like a big lump of JELL-O!

2. Protection--Several of your bones make strong enclosures for some important parts of your body. Your cranium protects your brain. Your ribs protect your heart and lungs. Your backbone, or vertebra, protects the main channel of your nervous system, your spinal cord.

3. Movement--Your skeleton helps you move around. In this it is helped by your muscles. Wherever two bones come together, there is a joint. Some joints let you bend a part of your body.

A ball-and-socket joint (shoulder and hip)--lets you move in many directions. Hinge joints (knee and elbow) move up and down. Your wrist and ankle are pivot joints, which help you move your hands and feet around in different directions.

As you get older, your bones grow along with you (or maybe you're growing along with your bones!). It is important to make sure you have enough calcium in your diet to help your skeleton stay strong and healthy

One more surprise: In those hollow spaces inside your bones there is a mushy material called marrow. Bone marrow is where your body makes new blood cells.

Next time you think about it, say a big "thanks" to your skeleton. It holds you up, helps you move around, protects your insides, and helps your blood supply stay in good shape.

Make no bones about it; you wouldn't be here without your skeleton!