How do lungs work? - Emma Bryce — Transcript

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1. 0:06Many of us have hundreds of things on our minds at any moment,
2. 0:09often struggling to keep track of everything we need to do.
3. 0:13But fortunately,
4. 0:14there's one important thing we don't have to worry about remembering:
5. 0:18breathing.
6. 0:19When you breathe, you transport oxygen to the body's cells to keep them working
7. 0:23and clear your system of the carbon dioxide
8. 0:26that this work generates.
9. 0:28Breathing, in other words, keeps the body alive.
10. 0:31So, how do we accomplish this crucial and complex task
11. 0:34without even thinking about it?
12. 0:36The answer lies in our body's respiratory system.
13. 0:39Like any machinery, it consists of specialized components,
14. 0:43and requires a trigger to start functioning.
15. 0:45Here, the components are the structures and tissues making up the lungs,
16. 0:49as well as the various other respiratory organs connected to them.
17. 0:53And to get this machine moving, we need the autonomic nervous system,
18. 0:57our brain's unconscious control center for the vital functions.
19. 1:01As the body prepares to take in oxygen-rich air,
20. 1:04this system sends a signal to the muscles around your lungs,
21. 1:08flattening the diaphragm
22. 1:09and contracting the intercostal muscles between your ribs
23. 1:12to create more space for the lungs to expand.
24. 1:16Air then wooshes into your nose and mouth,
25. 1:18through your trachea,
26. 1:19and into the bronchi that split at the trachea's base,
27. 1:23with one entering each lung.
28. 1:25Like tree branches, these small tubes divide into thousands of tinier passages
29. 1:30called bronchioles.
30. 1:31It's tempting to think of the lungs as huge balloons,
31. 1:34but instead of being hollow, they're actually spongy inside,
32. 1:38with the bronchioles running throughout the parenchyma tissue.
33. 1:41At the end of each bronchiole is a little air sack called an alveolus,
34. 1:46wrapped in capillaries full of red blood cells
35. 1:49containing special proteins called hemoglobin.
36. 1:52The air you've breathed in fills these sacks,
37. 1:54causing the lungs to inflate.
38. 1:56Here is where the vital exchange occurs.
39. 1:58At this point, the capillaries are packed with carbon dioxide,
40. 2:02and the air sacks are full of oxygen.
41. 2:05But due to the basic process of diffusion,
42. 2:07the molecules of each gas want to move to a place
43. 2:11where there's a lower concentration of their kind.
44. 2:13So as oxygen crosses over to the capillaries,
45. 2:16the hemoglobin grabs it up,
46. 2:18while the carbon dioxide is unloaded into the lungs.
47. 2:21The oxygen-rich hemoglobin is then transported throughout the body
48. 2:25via the bloodstream.
49. 2:26But what do our lungs do with all that carbon dioxide?
50. 2:29Exhale it, of course.
51. 2:31The autonomic nervous system kicks in again,
52. 2:34causing the diaphragm to ball up,
53. 2:36and the intercostal muscles to relax,
54. 2:38making the chest cavities smaller and forcing the lungs to compress.
55. 2:42The carbon dioxide-rich air is expelled, and the cycle begins again.
56. 2:46So that's how these spongy organs keep our bodies efficiently supplied with air.
57. 2:51Lungs inhale and exhale between 15 and 25 times a minute,
58. 2:55which amounts to an incredible 10,000 liters of air each day.
59. 2:59That's a lot of work, but don't sweat it.
60. 3:01Your lungs and your autonomic nervous system
61. 3:04have got it covered.