1. The Respiratory System

2. The Respiratory System
The main function of the ______________________________ is to help us breathe.
When we breathe our body can exchange CO₂ (_____________________) for O₂ (______________).
The respiratory system is made up of the ________________, _____________, and _____________________.

4. How does the respiratory system work?
The _________________ muscle contracts and relaxes to change the air ________________ in our body.
A change in pressure causes us to either release air or draw air in.
Air enters through the _____________ or ______________ and travels down the ___________________ to the ______________.

5. The Lungs
Inside the lungs there are narrow tubes called ________________________.
The bronchial tubes lead to the _______________.
Alveoli are tiny sacs _________________ by ___________________.
In the alveoli blood picks up ______and drops off ______