1. The Respiratory System

2. A system in which gases are exchanged.

3. Did you know… A person can go without food for about 9 days… A person can go without water for only 3-4 days… But a person cannot go without air for more than a few minutes!

4. Breathing! Breathing is the means by which our bodies obtain and release gases Those gases are: Oxygen (O2) Carbon Dioxide (CO2)

5. Follow the Pathway 1. Breathe In!! This is called Inhalation Gases are inhaled through your nose or mouth Air is a mixture!! 21% oxygen 78% nitrogen

6. Follow the Pathway - Start 2. From the nose, air travels through to the pharynx. This is the upper throat and nose. The pharynx is shared – both food and air travel through it.

7. Follow the Pathway 3. From the pharynx, air travels through the larynx, or voicebox. The epiglottis is a fold of tissue that covers the laryngeal opening. This prevents food from entering.

8. Follow the Pathway 4. From the larynx, air travels into the trachea, or windpipe. This strong pipe is made of cartilage and tissue so that it stays open and will not collapse.

9. The Pathway 5. The trachea branches into two smaller tubes called the bronchi. The two bronchi branch into smaller and smaller branches called bronchioles.

10. The Pathway 6. The smallest bronchioles end in the alveoli, or air sacs. It is in these tiny sacs that gas is exchanged.

11. The Pathway The alveoli increase the surface area in your lungs. If spread out, it would cover the surface of a tennis court! That’s over 2800 square feet!

12. Gas Exchange The exchange of gases is possible by diffusion – the movement of molecules from high concentration to low concentration

13. The air we breathe… The air we breathe isn’t always the cleanest …

14. Built-In Protection Goblet cells are cells that line the bronchi and trachea. They produce mucus.

15. Built-In Protection The cilia on surrounding cells move the mucus up and out of the lungs and into the trachea, where it is swallowed. Microbes trapped in the mucus are destroyed in the stomach by stomach acid.

16. Lungs Protected behind the ribcage, the lungs are the largest internal organs in the human body. They are surrounded by two layers of tissue called pleura.

17. The Diaphragm The diaphragm is a powerful muscle spanning the rib cage under the lungs. During contraction, the diaphragm descends (moves downward). This causes the lungs to fill up with air.

18. Breathing in vs. Breathing out Inhalation Is a more difficult process. In inhalation, external rib muscles and diaphragm contract and the chest cavity increases. Exhalation Is the easier process. During exhalation, rib muscles and diaphragm relax. Air pressure inside is greater than air pressure outside, so air rushes out like a leaky balloon

19. Did you know… Carbon dioxide level have a greater effect on breathing than oxygen levels do? Receptors found in your arteries signal the brain if too much CO2 is in the blood Too much CO2 in the blood is toxic and can damage the heart’s ability to beat.

20. Gas Transport Oxygen TransportCarbon Dioxide Transport It is taken in during inhalation. Oxygen enters the lungs & into the alveoli. It diffuses across the alveolar membranes and into the red blood cells. As oxygen-poor blood is entering the lungs, the CO2 diffuses out of the red blood cell and into the alveoli. It is released upon exhalation.

21. Gas Diffusion