1. The Respiratory system

2. Parts Divided into 2: Respiratory Tract The Lungs Nasal cavity Pharynx
Trachea
Bronchi
The Lungs
Alveoli

3. Role of System Gaseous exchange between surrounding air and blood
Oxygen diffuses from alveoli to blood
Carbon dioxide diffuse out from blood to alveoli

4. Function of Nasal Cavity
Filters air with hairs
Warm and moisten air with mucus

5. Function of Lungs
Where gas exchange occurs between the body and the outside world

6. Mechanics of Respiration
2 important structures
Intercostal muscles (muscles located between the ribs)
Diaphragm (muscle that seperates rib cage from abdomen)

7. Inhalation Air rich in O₂ and poor in CO₂
Intercostal muscles and diaphragm contract
Ribs rise
Diaphragm descends
Rib cage ↑ in size
Lung volume ↑
Air pressure ↓
O₂ rich air from outside flows into lungs until pressure inside and outside of lungs is equal

9. Exhalation Air rich in CO₂ and poor in O₂
Intercostal muscles and diaphragm relax
Ribs descend
Diaphragm rises
Size of rib cage ↓
Lung volume ↓
Air pressure ↑
CO₂ rich air inside lungs flows outside until pressure inside and outside lungs is equal

11. Gas exchange within the lungs
The O₂ that has been absorbed by the lungs must reach all the cells of our body!
This is why our blood needs to be circulated
The same goes for the waste product produced (CO₂) needs to be carried by the blood to be expelled from the body
This exchange of gases occurs in the ALVEOLI

12. Gas exchange within the lungs
Alveoli→ miniature sacs that fill with air and make up the bulk of the lungs
Each alveoli is surrounded by blood vessels called capillaries
When the blood reaches the alveoli, it is CO₂ rich
The air in the alveoli is O₂

13. Gas exchange