GAS EXCHANGE

• Did you know that your body has its very own gas exchange program that runs 24 hours a day? It’s called the respiratory system. It is one of your body’s vital systems, which means you could not live without it. Every time you take a breath, oxygen enters your lungs and is carried around to all the body’s cells by the circulatory system. Waste products, like the gas carbon dioxide, are picked up by the circulatory system as well. Carbon dioxide is dropped off back at the lungs so you can breathe it out. The respiratory and circulatory systems need each other. The respiratory system brings in oxygen and pushes out carbon dioxide, and the circulatory system transports these gases where they need to go. The two systems work together to make sure that your body gets what it needs to survive. That is why we say that the respiratory and circulatory systems are interdependent. They need each other.
• The respiratory system is not just your lungs. It also includes your nose, mouth, and the air passage ways that connect them to your lungs. After you inhale air through your nose and mouth, it enters a tube in your throat called the trachea. Just before the trachea gets to your lungs, it splits into two smaller tubes called the bronchi. The deeper you go down into your lungs, the smaller and smaller the tubes become as they keep dividing in two. The very smallest tubes end with tiny sacs that look kind of like grape clusters under the microscope. These are called alveoli. They are tiny air sacs that diffuse oxygen into the blood, and receive carbon dioxide being returned to the lungs in the blood. Carbon dioxide travels back out of your body when you exhale.
• Your body has a special way of making sure that you can get the oxygen that you need when you breathe. Your chest actually changes size when you inhale. You have muscles that are attached to your ribs. These muscles pull up when you inhale. Your diaphragm, a large muscle under your lungs, pulls down. This gives you plenty of room to take nice, deep breaths so you can get the air you need.

Name:_________________________________

Answer the following questions based on the reading passage. Don’t forget to go back to the passage whenever necessary to find or confirm your answers.

1)   Writing can be written in first, second, or third person’s point of view. What is the point of view of this passage?

2)   Identify the parts of the respiratory system.

3)   What is the function of the alveoli?

4)   Predict what might happen if the carbon dioxide did not get picked up by the circulatory system.

5)   Feel your chest as you breathe in deeply. What is happening in your body?