The respiratory system allows air to enter the body through the nose or mouth and then passes through multiple structures down to the lungs. Air is warmed, cleaned, and moistened as it passes through the nasal cavity. It then travels through the pharynx, larynx, trachea, bronchi and bronchioles before reaching the alveoli in the lungs. In the alveoli, oxygen from the air enters the bloodstream and carbon dioxide moves from the blood into the air to be exhaled. Smoking damages cilia and alveoli, impairing gas exchange and increasing risks of diseases like emphysema and lung cancer.

1. RESPIRATORY SYSTEM

2. RESPIRATORY SYSTEM

3. RESPIRATORY SYSTEM As air enters the body, it enters through the following structures: 1) Nose (or oral cavity if you breathe with your mouth) 2) Pharynx 3) Larynx 4) Trachea

6. RESPIRATORY SYSTEM Larynx (“voice box”) Houses the vocal cords.

7. RESPIRATORY SYSTEM Larynx (“voice box”) Act like strings of a guitar ( relaxed for lower pitch , and tightened for higher pitch ) Male vocal cords grow during puberty, like thicker guitar strings, causing voice to deepen

9. RESPIRATORY SYSTEM Vocal cord nodules Growths on the vocal cords. (from constant straining of voices)

10. RESPIRATORY SYSTEM Trachea : The trachea is lined with ciliated cells , which brush foreign particles back upwards It also maintains its rigidity thanks to cartilage (soft “bone”)

11. RESPIRATORY SYSTEM Trachea : The epithelium of the trachea has mucous cells (Goblet cells) and cilia . The mucus traps foreign particles , and cilia brush the mucus up the trachea (like mopping the floor)

12. RESPIRATORY SYSTEM Trachea : We sneeze to expel mucus that has trapped foreign particles, as well as other inhaled particles

13. RESPIRATORY SYSTEM Bronchus : The trachea leads into the bronchus ( like a fork in the road ), which further divides into smaller bronchi . The structures are also reinforced with cartilage .

14. RESPIRATORY SYSTEM Bronchi : The bronchi branch into the lungs, eventually reaching the alveoli .

15. RESPIRATORY SYSTEM Alveoli : The alveoli (singular: alveolus ) are spherical hollow cavities which increase surface area for gas exchange. Capillaries (tiny blood vessels) line the alveoli to make gas exchange possible.

16. RESPIRATORY SYSTEM Alveoli : Low-oxygen blood ( bluish color ) travels to the alveoli where carbon dioxide is released. At the same time, oxygen from inhaled air enters the blood, making it look red .

17. RESPIRATORY SYSTEM Alveoli :

18. RESPIRATORY SYSTEM Gas exchange: Carbon dioxide (a waste product) leaves the blood vessel into the alveolus. Oxygen goes into the blood vessel. CO 2 CO 2 CO 2 CO 2 O 2 O 2 O 2 O 2 Blood vessel Alveolus

19. RESPIRATORY SYSTEM Lung surfactant: Surfactant helps to lower surface tension in the airways and this helps keep the lung alveoli open . Also has immune cells to defend against bacteria, viruses, and other infectious agents.

20. RESPIRATORY SYSTEM The Lung: Each lung is divided into lobes. The right lung has three lobes. The left lung has two lobes (to accommodate the heart).

21. RESPIRATORY SYSTEM Pleura: The lungs are protected by a layer called the pleura . Pleura is a flexible membrane that permits the lung to expand and contract during inspiration and expiration .

22. RESPIRATORY SYSTEM Breathing: When we breathe we use two sets of muscles: 1) Diaphragm – separates the lungs (thoracic cavity) from the stomach and liver 2) Intercostal muscles (ribcage muscles)

32. RESPIRATORY SYSTEM Lung volumes A highly trained athlete may have a lung capacity as great at six and a half liters, nearly 50 percent greater than an average adult. Our lungs can be trained over time to take in more oxygen as our bodies need it. Exercise that improves lung capacity is called aerobic exercise . Increasing the capacity of your lungs will mean that you need to breathe fewer times in a minute for your body to receive the same amount of oxygen as a person with smaller lung capacity.

33. RESPIRATORY SYSTEM Lung volumes and disease: 2 types: Restrictive: Lung volumes are decreased  ex: pulmonary fibrosis

34. RESPIRATORY SYSTEM Lung volumes and disease: 2 types: Obstructive: Lung volumes are normal but flow rates are impeded  ex: asthma

35. RESPIRATORY SYSTEM ASTHMA: Air pollution can lead to asthma. Asthma is a chronic , inflammatory disease resulting in reversible airflow obstruction.

36. RESPIRATORY SYSTEM SMOKING: Smoking injures the cilia of the trachea, and alters the efficiency of their beating so they cannot remove foreign particles (i.e. bacteria ) as effectively. Tar builds up in the lungs from smoking. Tar decreases respiration.

37. RESPIRATORY SYSTEM SMOKING: Smoking causes emphysema . - alveoli walls fuse together, which reduces the surface area for gas exchange.

38. RESPIRATORY SYSTEM SMOKING: Lung with emphysema

39. RESPIRATORY SYSTEM SMOKING: Lung cancer is associated with smoking.