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The Human Body.

Systems at Work.

The human body is amazing for many reasons.

First of all, it is made up of many parts.

Each part is special and has an important job to do.

Secondly, all of the parts work together in systems that do even bigger jobs.

In addition, all of those systems work together as one unit, so that you can live a happy and healthy life.

In ancient times, people used to think differently about the human body.

Today, we know that there are over ten major systems in the human body.

Let's look at how two of these systems work together for your good health.

The Respiratory System.

This system first brings oxygen into your lungs.

It takes carbon dioxide out of your lungs.

The respiratory system has three major parts, the trachea, the lungs, and the diaphragm.

The Circulatory System.

This system first carries blood containing oxygen and nutrients to all of the cells in your body.

It then removes carbon dioxide and other waste products from those cells.

The circulatory system has four major parts, the heart, the arteries, the veins, and the capillaries.

Blood moves through these parts.

Two Systems Working Together as One.

When you breathe in, your diaphragm first moves down so your lungs can get bigger.

As a result, air flows into your nose or mouth through your trachea and into your lungs.

This air has oxygen in it, which your body needs to live.

Next, this oxygen goes into the blood of the capillaries inside your lungs.

The capillaries carry this oxygen-rich blood to the pulmonary veins.

These veins then take this blood to the left side of your heart.

Next, your heart pumps this blood into thick tubes called arteries.

The arteries then carry this blood to all of the cells in your body.

The cells use the oxygen in this blood to keep your body healthy.

While your cells use the oxygen, they also create carbon dioxide after they use the oxygen.

Your body doesn't need carbon dioxide, so the blood in your veins carries the carbon dioxide back to the right side of your heart.

The heart then pumps this blood into your lungs.

After this happens, the carbon dioxide in this blood goes back into the air in your lungs.

Finally, your diaphragm moves up and squeezes your lungs, and the air in your lungs goes out of your nose or mouth.

These two systems work well together.

They bring oxygen-rich blood to every part of your It is easy to see why the human body is called the most amazing machine in the world.

You breathe about 20,000 times every day.

Check your lung power. 1.

Get a package of large balloons.

Make sure they are all the same size.

Give one to each friend. 2.

Tell everyone to blow once into their balloons, filling them as much as possible.

Then, measure the balloons.

Whose is the biggest?

Put your two fists together.

This is about the size of your heart.

Check your heartbeat. 1.

Place two fingers on your wrist below your thumb.

Can you feel blood moving through the artery?

This is your pulse, which you can count to measure your heartbeat. 2.

Count the number of beats you feel in one minute.

Compare your heartbeat with your friend's.

Thank you for watching.