The Skeletal System

Lesson Plan - Get It!

Audio:

Certain foods, like milk, contain calcium, a substance that helps make our bones stronger.

• Why do you think it is important to have strong bones?

It would be hard to play outside or compete in sporting events if your bones were weak! The bones in your body make up your skeletal system. An adult has 206 bones, each with a unique function!

Before moving on, if you missed or need a review of any The Human Body lessons, find them in the right-hand sidebar under Related Lessons.

Some of our bones help protect organs. Your skull protects your brain, while your rib cage keeps your heart and lungs safe. Other bones provide structure, like the bones in your legs that help you stand and sit.

• Did you know that the skeletal system also includes tendons, ligaments, and cartilage?

You may have heard of someone tearing a ligament, or about the cartilage found in sharks. These tissues connect bones so they work together correctly.

Tendons are bands of fibrous tissue that assist bones in moving. Try wriggling your fingers while looking at the back of your hand. You can see tendons moving as they connect your muscles to your finger bones and hand bones.

Cartilage is a tough material that helps provide structure to body parts. We have cartilage in the upper part of our ears. Feel your ear, and describe what you feel in five words.

Cartilage is also found in joints. A joint is where two bones meet in the body, like your elbow or knee. Cartilage helps joints move smoothly so you are not in pain as you move.

Bones are made up of minerals and living tissue. As you learned earlier, calcium plays an important role in building the outer layer of the bone. This layer is durable, solid, and smooth. It surrounds a spongy material inside the bone. The spongy inner layer helps our bones stay light.

• Why do you think it is important that our bones are not heavy?

It would be hard to move around!

Bone marrow is produced in the spongy layer. Bone marrow is an extremely important substance because it helps us make red and white blood cells. When you are born, your bone marrow can make up to five billion red blood cells!

Review time: The skeletal system provides structure and protection to organs and tissues in the body. It helps us grow and develop from infancy to adulthood. Bones made up of two layers of materials make up the skeletal system. There are some muscles that assist bones in movement, too!

1. With a parent or teacher, list three functions of the skeletal system.
2. Then, draw a quick picture of the structure of bones.

In the Got It? section, you will learn more about bones throughout the body.