1. The Respiratory System

2. What is the Purpose? The respiratory system allows oxygen to enter the blood and carbon dioxide to exit the blood. We would not be able to breathe without our respiratory system.

3. Main Parts The main parts of the respiratory system include the trachea, the lungs, and the diaphragm.

4. Main Parts The trachea (windpipe) is a long tube in your neck and chest that carries air in and out of your lungs. The lungs are the main organ of the respiratory system. The diaphragm is a flat muscle below the lungs that contracts when you inhale and relaxes when you exhale.

5. Gases You breathe oxygen into your lungs and it is transported to the rest of your body through the circulatory system. You breathe out carbon dioxide, a waste product of your cells.

6. Inside the Lung The bronchial tubes, bronchioles, and alveoli work together to transport the oxygen and carbon dioxide. Bronchial tubes are tubes that branch off into the left and right lungs. Bronchioles are tiny tubes that branch off from the bronchial tubes, transporting air into the lungs. Alveoli are tiny air sacs in your lungs that exchange carbon dioxide for oxygen. They are located at the end of each bronchiole.

7. Bronchial Tubes and Bronchioles Bronchial Tube

8. Alveoli