A short powerpoint presentation into the Biological workings of inhalation and exhalation (suitable for high school level).

1. HOW DO WE BREATH?

2. VENTILIATION OF THE LUNGS
-The movement of respiratory muscles changes the volume of the thoracic cavity
- This changes the pressure
- The difference in pressure between the atmosphere and the air in thoracic cavity
brings about ventilation:
1. INHALATION
2. EXHALATION

3. Remember the respiratory muscles?

4. MECHANISM of inhalation

5. MECHANISM of inhalation
1. The diaphragm contracts (dome
shape flattens)
2. The thoracic cavity enlarges from top
to bottom
3. The intercostal muscles contract
4. The thoracic cavity enlarges from
side to side and front to back
5. Total volume of thoracic cavity
increases (pressure decreases)
6. Lungs expand – air rushes in

6. MECHANISM of exhalation

7. MECHANISM of exhalation