1. Respiratory System

3. Inhaling and Exhaling Inhaling and Exhaling Video Clip from AdamInhaling and Exhaling Video Clip from Adam

4. Human Respiratory System

5. First: Mouth and Nose Air, containing the oxygen our bodies need, is inhaled through the mouth and the nose. The mucus membranes in our mouth and nose warm and moisten the air, as well as trap particles of foreign matter.

6. Epiglottis This little flap makes sure none of your food gets into your lungs. That's why you can't swallow and breathe at the same time!

7. Cilia Little hairs called cilia act like tiny brooms to push the dirty mucus out of your lungs and into your throat. *Lung Cilia animationLung Cilia **Smokers CiliaSmokers Cilia

8. Lungs and Gas Exchange Lungs and Gas Exchange Our lungs bring fresh oxygen into our bodies and remove carbon dioxide and other gaseous waste products.

9. Diaphragm As we breathe air in, we use the muscles of our rib cage and especially the major muscle called the diaphragm to pull air into our lungs.

10. Lung Models

11. How Diaphragm Works As the diaphragm is pulled down, the volume of the cavity increases. This causes the pressure to fall. Air rushes in to equalize the pressure causing the balloons to inflate. volumepressureAir As the diaphragm is pushed up, the volume of the cavity decreases, the pressure rises, and the air rushes out of the balloons causing them to deflate.

12. Trachea The air passes through the throat into the trachea or windpipe. Very hard tough rings are around it. Feel the front of your neck. Can you feel your trachea?

13. Bronchi The trachea divides into the left and right bronchi. Each bronchus divides again and again, becoming narrower and narrower.

14. Alveoli The smallest airways end in the alveoli, small, thin air sacs that are arranged in clusters like bunches of balloons.

15. Alveoli -breathe in by enlarging the chest cage, the "ballons" expand as air rushes in to fill the vacuum. -breathe out, the "balloons" relax and air moves out of the lungs. Gas Exchange Video - Adam

16. Alveoli Tiny blood vessels surround each of the 300 million alveoli in the lungs.

17. O 2 and CO 2 Exchanges

18. Comparing Breathing Organs

19. Oxygen in Water flows over gills

20. Insect Breathing

21. Air Sacs in Birds

22. Mammals