The respiratory system takes in oxygen and removes carbon dioxide, providing energy for cells. Air moves through the nose, pharynx, larynx, trachea, bronchi and into tiny alveoli in the lungs where gas exchange occurs. Breathing is a two-step process of inhalation, where the ribs expand and diaphragm contracts, and exhalation, where the ribs relax and diaphragm relaxes. Damage from smoking can cause lung cancer, emphysema and bronchitis due to tar and other chemicals.

1. Respiratory System
6th Grade Science

2. I. Function
A. Take in oxygen from air
B. Remove carbon dioxide
C. Provides Energy for all cells
D. Smell
E. Water balance
F. Communication

3. II. Air Exchange
A. Inhaled Air
1. Nitrogen 78%
2. Oxygen 21%
3. Carbon Dioxide 0.03%
B. Exhaled Air
1. Nitrogen 78%
2. Oxygen 16%
3. Carbon Dioxide 4%

4. III. Pathway
A. Nose
1. Hairs and mucus – Clean Air
2. Nasal Membranes – Warm and moisten Air
3. Sinuses – Air chambers

5. B. Uvula
1. Close off nose during swallowing

6. C. Pharynx
1. Throat
i. Shared with dig.

7. D. Larynx
1. Allows speech (vocal cords control)

8. E. Trachea
1. Wrapped in cartilage ring to keep open
2. Cilia to sweep stuff out of lungs
i. Bring up to pharynx for swallowing
ii. Contract violently if irritated – sneeze

9. F. Bronchi
1. Branches into each lung
2. Continued until reached end

10. G. Alveoli
1. Tiny sacs for gas exchange
i. Oxygen into blood
ii. Carbon dioxide into alveoli
2. Numbers – 300 million
3. Area – 7 meters2

11. IV. Breathing
A. Two step process
1. Inhalation
i. Ribs move out
ii. Diaphragm pulls down
2. Exhalation
i. Ribs relax
ii. Diaphragm relax
iii. Pull in intestines

12. V. Speech

13. VI. Damage and Disease
A. Smoking
1. ~1,100 deaths every day
2. 4,000 different chemicals
i. Tar – Chemicals that coat airways
ii. Carbon Monoxide – Replaces oxygen in blood
iii. Nicotine – Addictive stimulant

14. B. Asthma
1. Blocking of airways inappropriately
1. Inhalers used to relax muscles

15. C. Bronchitis
1. Blocking of airways from pollution

16. E. Emphysema
1. Lung damage – No gas exchange

17. F. Lung Cancer
1. 400 people each day
2. 53 cancer chemicals in cigarettes

18. G. Atherosclerosis
1. Tar chemicals harden arteries
i. Smokers have twice as many heart attacks