Muscles: The Movement of Joints

Lesson Plan - Get It!

Audio:

There are a lot of joints in your body!

From the previous Related Lessons in the Bones series, found in the right-hand sidebar, you have discovered that your body requires specific joints in order to move in differnt directions. A joint is an area where two bones come together.

• There are 206 bones in the human body; can you guess how many joints there are in your body?

Humans have a total of 360 joints, but only 240 are movable joints, like the joints we studied in the previous lessons. Still, 240 is a lot of joints, but they can't move on their own. They need muscle power!

Even though joints are key to bone movement, they need muscles to make them move. Think about this: If you were to put two pencils end-to-end, they would not be able to stay together or move unless YOU moved them!

• Since joints are the meeting point between two bones, how are they held together?
• What makes them able to bend?

It's time to visit Dr. Jo and find the answers to some of these questions:

Muscles are very important to the functions of the body. Even if you had joints, you would not be able to move them without muscles. When a muscle contracts, a joint bends with it. When the muscle relaxes, the joint is able to relax and unbend. Moving your joints is only one of the many jobs that muscles have, but it sure is an important job!

• What would simple daily tasks be like if you didn't have muscles to move your joints?

Move on over to the Got It? section to check your brain!