1. Respiratory System
C-Scope 2010
Unit 5, Lesson 3

2. Fun Facts Each lung is about the size of a football.
They fill the area from the collarbone to the bottom of the ribs.
They are the only organ in the body light enough to float.

3. Fun Facts
There are enough alveoli in the lungs to cover a tennis court.
If all the capillaries that surround the alveoli where laid end to end, they would extend km or 620 miles.

4. Respiratory System
Under control of the involuntary and voluntary nervous system.
The autonomic NS controls breathing in response to CO2 in the blood.
The somatic NS controls breathing when you decide to hold your breath.
The autonomic system takes over when you pass out from holding your breath, until you blood gases return to normal.

5. Inhalation
The diaphragm and the intercostal muscles (the muscles between your ribs) contract and expand the chest cavity.
The expansion lowers the pressure on the chest cavity below the outside air pressure.
Air flows in (always from high pressure to low pressure) and inflates the lungs.

6. Exhalation
The diaphragm and the intercostal muscles relax and the chest cavity gets smaller.
The decrease in volume of the cavity pushes the air out of the lungs.
The cycle repeats with every breath.
You breathe in and out 15 to 25 times a minute without thinking about it.

7. Alveoli Nasal Cavity Little air sacs at the end of the bronchi.
Exchange the gases with the blood
Nasal Cavity
Moistens the air
Warms up the air

8. Diagram Epiglottis Pharynx Larynx Trachea Bronchial Tubes Alveoli
Diaphragm