1. Notes: Respiratory system

2. The Passage of Air Through the Body 1. The air that enters the body is filtered and warmed in the nose. 2. The air will then pass into the pharynx, a tube in the throat where the passageways for air and food pass. 3. Air moves from the pharynx and past the epiglottis (a flap of tissue that opens the airway when you breathe and closes it when you eat). 4. At the top of the trachea is the larynx, which contains the vocal cords.

3. 5. The trachea then forks into two bronchi. 6. These two branches take the air into the lungs to exchange oxygen with carbon dioxide with the blood. 7. Branching of the air tubes continue into smaller and smaller tubes known as bronchioles. 8. Finally, the oxygen makes it to tiny air sacs called the alveoli that are surrounded by moisture (lined with mucus to trap foreign particles) where the oxygen is dissolved.

4. Gas Exchange Oxygen (O2): crosses the capillary walls from the alveoli (lungs) into the blood. Carbon Dioxide (CO2): in opposite direction, goes from the blood inside the capillaries back into the lungs. Breaths: 15 per minute, 21,000 per day! Remember: Oxygen you breathe in is transferred to the blood, while carbon dioxide in the blood is dropped off back at the lungs, ready for you to exhale.

5. _______

7. TERMS: Tidal Volume: Normal amount of air breathe in and out. Vital Capacity: Complete exhalation - amount of oxygen forced out of lungs. Residual Volume: Amount of air always in lungs, even after you exhale. Lung Capacity: Total amount of oxygen in lungs after maximum inhalation.