1. The Respiratory System

2. The Respiratory System
The main function of the respiratory system is to help us breathe.
When we breathe our body can exchange CO₂ (carbon dioxide) for O₂ (oxygen).
The respiratory system is made up of the trachea, lungs, and diaphragm.

3. nose and mouth
trachea
lungs
diaphragm

4. How does the respiratory system work?
The diaphragm muscle contracts and relaxes to change the air pressure in our body.
A change in pressure causes us to either release air or draw air in.
Air enters through the nose or mouth and travels down the trachea to the lungs.

5. The Lungs
Inside the lungs there are narrow tubes called bronchial tubes.
The bronchial tubes lead to the alveoli.
Alveoli are tiny sacs surrounded by capillaries.
In the alveoli blood picks up O₂ and drops off CO₂