The respiratory system

1. Functions of the respiratory system

1.1. We breathe to live

1.2. We breathe faster when we exercise because we need more air

2. Motions of breathing

2.1. Inhalation

2.1.1. When you breathe in, the diaphragm moves down and the lungs fill with air

2.2. Exhalation

2.2.1. When you breathe out, the diaphragm moves up and the lungs empty

3. Parts of the respiratory system

3.1. 1. Nose

3.1.1. It cleans the air

3.2. 2. Trachea

3.2.1. It is a long tube in the neck. It cleans the air

3.3. 3. Bronchi

3.3.1. Two tubes

3.4. 4. Bronchioles

3.4.1. Small tubes connected to the bronchi

3.5. 5. Lungs

3.5.1. Two spongy sacs

3.6. 6. Alveoli

3.6.1. Very small sacs inside the lungs