1. Aim: How does air travel through the respiratory system?

2. Weird Science Fact
Normal Breathing rate is respirations/minute. 17,280 – 25,920 times every day.
If you spread out your lungs, they would cover the floor of a racquetball court (about 70 square yards).
Men can hold about 6 quarts of air in their lungs. Women can hold about 4.5 quarts.
A sneeze shoots air out of your lungs at 100 miles per hour! (650?)

3. Pathway Nasal Passage Pharynx Trachea Bronchial Tubes Bronchioles
Alveoli

4. Nose and Nasal Passage
The air enters the nose and is filtered, warmed and moistened before entering the lungs.
Pharynx
Back of the throat
Epiglottis covers the windpipe

5. Trachea Bronchial Tubes
Windpipe
Rings of cartilage keep it open
The larynx (voice box, located at top)
Cilia lined
Bronchial Tubes
Bronchi – Two tubes branching from the trachea.
Bronchioles – smaller branches from the bronchi (looks like a tree).

6. Alveoli
Tiny (grape like) air sacs at the end of bronchioles surrounded by capillaries that increase the surface area of the lungs.
RESPIRATORY SURFACE, gas exchange takes place here.
About 300 million in our lungs.

7. Gas Exchange:
Carbon dioxide & oxygen are exchanged between capillaries and alveoli by the process of diffusion.

8. Pleura – membrane covering the lungs
Other Structures
Pleura – membrane covering the lungs
Diaphragm – flat muscle on the floor of the chest.
Pressure changes causes the lungs to expand and contract.

9. Inhalation/Exhalation
INHALATION: diaphragm moves down, ribs move up, chest cavity becomes larger, pressure decreases, AIR ENTERS!
EXHALATION: diaphragm relaxes, ribs drop, cavity becomes smaller, pressure increases, AIR EXITS!

10. The Breathing Rate is controlled by:
Concentration of carbon dioxide in blood
Control Center in brain and Carotid Bodies
Exercise
Foreign particles

11. Regulation of Breathing:
Breathing Rate is controlled by the amount of
CO2, not O2!!
Exercise CO2 H2CO3 Blood pH Breathing Rate