All About Bones

Chapter two All About Bones

Last time, we learned the names of some of the bones in the body. Today, I'd like to tell you a little more about bones.

The bone I'm pointing to is the human fibula bone. The fibula, you may recall, is one of the bones in your leg.

The outer part of a bone is hard. It is made up of the same stuff as a seashell you might find at the beach. That stuff is called calcium.

Do you like milk? Milk and other dairy products like cheese have lots of calcium in them. They are good for your bones. One way to take good care of your bones is to eat a healthy diet with dairy products and other foods that provide calcium like beans and green leafy vegetables.

Dr. Welbody points to the fibula.

If you could look inside a bone, you'd see something called bone marrow. Since you can't see inside this bone, I'll show you a slide.

This slide shows bone marrow cells. I think you may already know a little about cells. Is that right? If you look at things with a strong microscope, you can see that many things are made up of tiny cells. Your skin is made of cells. So are your bones.

Here you can see some bone marrow cells. There are millions of cells like these inside your bones. The bone marrow cells have an important job. They are like little factories. They produce red blood cells. Then, the red blood cells carry oxygen all around the body.

As you get older and taller, your bones grow with you. Bones are strong. They can support a great deal of weight. However, if we put too much pressure on them, or if the pressure comes from the wrong direction, bones can break.

This next slide shows a broken bone. This is a special kind of picture called an x-ray.

X-rays are part of the invisible light spectrum. When you aim x-ray light at your body, some parts of the body absorb a lot of x-rays and some do not. Your bones are hard. They absorb a lot of the x-ray light. The soft tissue around your bones absorbs less x-ray light. That is why doctors like x-rays. We can aim x-rays at a part of your body and get a picture of the inside of your body. We can use x-rays to find out if any bones are broken. You will learn much more about x-rays in a later unit about light and sound.

Have any of you ever broken a bone?

I fix lots of broken bones each year. Would you like to know how I do it?

I start by taking x-rays. That's how I find out if the bone is really broken. If the x-rays show that a bone is broken, then I set the bone. That means I put the bone pieces back in the right place. Once the bones are in the right place, I put on a cast.

One of the remarkable things about the bones in your body is that they are able to heal themselves. Once a broken bone has been set, it grows back just like it was before it was broken.

Here's a boy I fixed up last summer. He broke one of the bones in his arm. I put the cast on to hold the bones in the right place so they would heal. He had to wear the cast for two months while the bones healed. Then, I cut the cast off for him.

He's just fine now. His bone has healed and his arm is as good as new.

The cast helps the boy's broken arm heal.