1 00:00:09,480 --> 00:00:11,920 The respiratory system 2 00:00:11,920 --> 00:00:15,040 So the structure and function of the respiratory system. 3 00:00:15,040 --> 00:00:23,720 This is part of three that work together for cellular respiration; the circulatory system, the respiratory system and the digestive system. 4 00:00:23,720 --> 00:00:29,760 So with the respiratory system we draw in oxygen down through to the lungs 5 00:00:29,760 --> 00:00:34,160 into the structure known as the alveoli for gaseous exchange 6 00:00:34,160 --> 00:00:41,720 Oxygen is now in our blood and that is transported to all of our body's cells, for cellular respiration. 7 00:00:41,720 --> 00:00:53,200 Carbon dioxide as a waste product, is transported back towards the lungs and we can then breathe out the waste product of carbon dioxide. 8 00:00:53,200 --> 00:00:58,440 So with the respiratory system we have some really important structures. 9 00:00:58,440 --> 00:01:12,920 So what we are going to have a look at in this dissection is the epiglottis, the trachea, bronchi, bronchioles and the alveoli. 10 00:01:12,920 --> 00:01:31,000 Part of this system we also have the diaphragm that contributes to this vacuumed structure and it helps change the volume and pressures within this structure, which then draws in 11 00:01:31,000 --> 00:01:36,840 and forces out the air from our lungs. 12 00:01:36,840 --> 00:01:43,320 So when we look at this structure then, starting with this epiglottis. 13 00:01:43,320 --> 00:01:49,720 As you can see then, we've got this tubular structure coming down towards the lungs. 14 00:01:49,720 --> 00:01:55,040 We have also got a second tubular structure are the front. 15 00:01:55,040 --> 00:02:05,800 This here is the esophagus, part of our digestive system and this harder structure is known as the trachea, part of the respiratory system. 16 00:02:05,800 --> 00:02:17,040 Now it is extremely important that when you are eating or drinking fluids that you don't want any of that food or substance to go into your lungs. 17 00:02:17,040 --> 00:02:32,840 So because these tubes run parallel to one another, everytime that you swallow food, what happens, the food actually lands on top of this epiglottis 18 00:02:32,840 --> 00:02:46,800 pushing it downwards and therefore it is kind of like a slide really, the food is forced into the esophagus that continues to run down to the stomach. 19 00:02:46,800 --> 00:02:58,600 Rather than falling directly into the trachea which is going to cause a blockage and you would choke and obviously a risk to life. 20 00:02:58,600 --> 00:03:11,840 If we remove then, this structure at the top, we can have a closer look at the trachea. 21 00:03:11,840 --> 00:03:19,200 So what we can actually see with the trachea we have got this really hard cartilaginous material 22 00:03:19,200 --> 00:03:26,840 when we open it up, we will notice that it is not a complete ring of cartilage. 23 00:03:26,840 --> 00:03:36,640 What we actually see is that we have an opening at the front. So we refer to it as C-shaped rings. 24 00:03:36,640 --> 00:03:47,880 This opening then allows for contraction of the esophagus especially if you swallow larger volumes of food. 25 00:03:47,880 --> 00:03:55,800 So we've got this little bit of space here for those contractions of the esophagus. 26 00:03:55,800 --> 00:03:59,800 So what we can do in this dissection, I am now going to remove that esophagus. 27 00:04:08,920 --> 00:04:12,240 And again, cutting away from yourself, keeping that safety. 28 00:04:18,520 --> 00:04:31,120 So when we are working down this trachea then you probably can see a lot clearer now these C-shaped cartilaginous rings and I am going to cut down the opening. 29 00:04:34,920 --> 00:04:36,720 I can see really quite easy. 30 00:04:45,000 --> 00:04:51,200 And you can see those C-shaped structures inside. So it is not a continuous cartilaginous tube. 31 00:04:51,200 --> 00:04:58,800 Which is really important, because by having it as these separate C-sections, it allows mobility. 32 00:04:58,800 --> 00:05:10,960 The flexibility of the trachea, just as you would when you are moving and bending your own neck. We haven't got this solid, rigid structure. 33 00:05:10,960 --> 00:05:19,560 Having it as a cartilaginous structure aswell, it prevents the trachea from collapsing so it is always maintaining that the airways are open. 34 00:05:19,560 --> 00:05:24,520 Obviously for airflow into and out of the lungs. 35 00:05:24,520 --> 00:05:30,080 So for example, when you are laid in bed, whether you are flat on your back or laid on your side. 36 00:05:30,080 --> 00:05:37,480 The cartilage is making sure that airway is completely open rather than it collapsing with gravity. 37 00:05:37,480 --> 00:05:44,000 So the trachea, one tube that goes down towards the lungs. 38 00:05:44,000 --> 00:05:54,760 What you will also notice is that when we get to the bottom, the inferior aspect of the trachea, it splits into two. 39 00:05:54,760 --> 00:06:05,480 So we have the left hand side where this tube continues. 40 00:06:05,480 --> 00:06:07,560 And the right hand side 41 00:06:13,360 --> 00:06:21,120 And these are known as the bronchi. So the left bronchus and the right bronchus. 42 00:06:21,120 --> 00:06:28,360 Again if you see blood clots, perfectly normal. 43 00:06:28,360 --> 00:06:34,360 You should notice then, with the bronchi that we have again, these cartilaginous rings 44 00:06:34,360 --> 00:06:41,440 maintaining that the airways are always open down into the small structures of the lungs. 45 00:06:41,440 --> 00:06:53,160 But what you also may notice is that we have got these smaller tubes again, projecting away from each of the bronchus. 46 00:06:53,160 --> 00:07:03,080 So these smaller tubes, we find a network of these throughout the entire of the lung known as the bronchiole. 47 00:07:03,080 --> 00:07:12,720 So the larger bronchiole also has cartilaginous rings but then we have smaller bronchiole that don't have cartilaginous rings anymore. 48 00:07:12,720 --> 00:07:24,640 So what we could do, is if we continue to cut down the bronchus, following that tubular structure, into the lungs 49 00:07:29,680 --> 00:07:35,040 We can see even more bronchiole forming. 50 00:07:35,040 --> 00:07:40,160 What I'd like to do is remove the surface of this lung. 51 00:07:45,880 --> 00:07:47,960 And hopefully if you can hear 52 00:07:50,400 --> 00:08:02,680 It is like a very sponge material and this is because the lungs are made up of these microscopic air sacs known as alveoli. 53 00:08:02,680 --> 00:08:15,640 And it is the alveoli where we have the gaseous exchange of carbon dioxide and oxygen to your blood. 54 00:08:15,640 --> 00:08:26,120 Now once we have taken that top section, we can see all of these smaller bronchioles throughout that lung spongy structure. 55 00:08:26,120 --> 00:08:36,360 Many of them with cartilaginous rings keeping the airways open and the smaller ones start losing that cartilaginous structure. 56 00:08:36,360 --> 00:08:40,720 The alveoli, we can't see because it is microscopic. 57 00:08:40,720 --> 00:08:48,160 But you can certainly appreciate that all of this spongy material is what makes up the alveoli. 58 00:08:48,160 --> 00:08:59,360 And because of its size we have got this large surface area so as a result we have got a really efficient gas exchange that can take place. 59 00:08:59,360 --> 00:09:07,120 So oxygen from the alveoli into your blood, for oxygenated blood to go to your body's cells. 60 00:09:07,120 --> 00:09:12,560 And then the deoxygenated blood bringing the carbon dioxide back. 61 00:09:12,560 --> 00:09:21,360 Which then leaves the lungs, the blood into the alveoli for you to breathe out. 62 00:09:21,360 --> 00:09:30,320 So to summarise, oxygen you breathe in, draw the oxygen into your lungs. 63 00:09:30,320 --> 00:09:36,600 So as you are breathing in, the oxygen travels down the trachea 64 00:09:36,600 --> 00:09:39,680 splits into the bronchus 65 00:09:39,680 --> 00:09:48,440 so for example, down the left bronchus and we have these smaller structures of the bronchioles. 66 00:09:48,440 --> 00:09:55,400 The end of the bronchioles, the air sacs ofd the alvioli, the site of gaseous exchange. 67 00:09:55,400 --> 00:10:05,720 The oxygen leaves the alveoli into your blood. The circulatory system transports that blood to your body's cells for cellular respiration. 68 00:10:05,720 --> 00:10:14,440 The waste product of carbon dioxide comes back through towards the lungs through deoxygenated blood. 69 00:10:14,440 --> 00:10:24,200 To the alvioli, the site of gaseous exchange. The carbon dioxide leaves the blood into the alvioli, back through the bronchioles. 70 00:10:24,200 --> 00:10:30,600 Up the bronchus, out the trachea and then you breathe out the waste product.