WEBVTT 00:00:01.000 --> 00:00:04.000 Let's say that this is you. You're enjoying a nice sunny day 00:00:04.000 --> 00:00:09.000 and you decided to take a nice long deep breath of air. 00:00:09.000 --> 00:00:15.000 And of course when I say air the part that you probably care the most about is just the oxygen, 00:00:15.000 --> 00:00:21.000 part of that air, that's the part that we as humans need to survive. 00:00:21.000 --> 00:00:24.000 So you take a deep breath. Let's say you take it through your mouth, 00:00:24.000 --> 00:00:26.000 you take a deep breath through your mouth. 00:00:26.000 --> 00:00:30.000 And then lets say you take one more deep breath, a second deep breath, 00:00:30.000 --> 00:00:31.000 and then you take that one through your nose. 00:00:31.000 --> 00:00:36.000 And you might think, "Well, these are two totally different ways of getting in air." 00:00:36.000 --> 00:00:40.000 That's certainly how it looks when you look at the mouth and nose. 00:00:40.000 --> 00:00:42.000 They don't look like they have much in common. 00:00:42.000 --> 00:00:45.000 But the truth is that actually if you follow the air, 00:00:45.000 --> 00:00:50.000 it almost follows an identical path. 00:00:50.000 --> 00:00:56.000 The air is gonna go into the back of the throat really regardless of how you took it in. 00:00:56.000 --> 00:00:59.000 So here we have air coming in from the nose, 00:00:59.000 --> 00:01:03.000 in here yet air coming in from the mouth and they meet up in the back of throat. 00:01:03.000 --> 00:01:10.000 And then they go down down down, they go towards this thing that we call the Adam's apple. 00:01:10.000 --> 00:01:14.000 I'm gonna bring it up a little bit, you can see it more easily. 00:01:14.000 --> 00:01:19.000 But basically you bring up this, you see this Adam's apple right there. 00:01:19.000 --> 00:01:22.000 And actually you can go ahead and take a feel of you own Adam's apple. 00:01:22.000 --> 00:01:27.000 It's a pretty cool structure in the middle of your throat 00:01:27.000 --> 00:01:30.000 and everybody has it, that's the first thing I want to tell you, 00:01:30.000 --> 00:01:34.000 that everybody has it, not just men, women have it too. 00:01:34.000 --> 00:01:41.000 And the reason it's called an Adam's apple is because "Adam" is generally a boy's name. 00:01:41.000 --> 00:01:49.000 And so it's to remind us that usually men or boys have larger Adam's apples than girls. 00:01:49.000 --> 00:01:54.000 And if you're trying to find it, I also want to point that it's a notch here. 00:01:54.000 --> 00:01:57.000 And you if you can feel the notch with your fingers, 00:01:57.000 --> 00:02:00.000 in that case you have a nice clue as to where it is located. 00:02:00.000 --> 00:02:06.000 This is Adam's apple and what it does is, it helps you control your voice. 00:02:06.000 --> 00:02:08.000 And actually there's another name for Adam's apple. 00:02:08.000 --> 00:02:13.000 Another name for it, sometimes people call it the voice box. The voice box. 00:02:13.000 --> 00:02:21.000 And of course air is passing through the voice box in this kind of the entry way into the trachea. 00:02:21.000 --> 00:02:28.000 And so it actually allows me to make my voice very high or make my voice very low, 00:02:28.000 --> 00:02:34.000 depending on how you change the muscles around in that Adam's apple. 00:02:34.000 --> 00:02:39.000 So that's actually kind of a first cool thing I want to point out to you, that you can actually control your voice. 00:02:39.000 --> 00:02:44.000 I'm sure you knew this already but what you're using is the Adam's apple, your voice box. 00:02:44.000 --> 00:02:49.000 Now air keeps going, air is just gonna keeps making its journey down and 00:02:49.000 --> 00:02:54.000 specifically of course the part of air I said, you know, we care about is the oxygen. 00:02:54.000 --> 00:02:58.000 It's gonna keep making its journey down into the lung areas, 00:02:58.000 --> 00:03:05.000 now the lung areas, it's gone down the trachea and it goes into the two lungs, the right and left lungs. 00:03:05.000 --> 00:03:11.000 This is the left lung, I'm gonna put L for left and this is the right lung, I'll put R for right. 00:03:11.000 --> 00:03:14.000 And immediately you'll think, "Wait a second, aren't they switched?" 00:03:14.000 --> 00:03:19.000 Now I want you to remember that this is from the perspective of the person who owns the lungs. 00:03:19.000 --> 00:03:23.000 So that's why I put it in left where I put it, in right where I put it. 00:03:23.000 --> 00:03:26.000 Now we should probably go ahead and start labelling some of these. 00:03:26.000 --> 00:03:30.000 You can see that the lungs actually don't look identical, right? 00:03:30.000 --> 00:03:34.000 They look slightly different, for example, this one has three lobes. 00:03:34.000 --> 00:03:40.000 The right side has three lobes called the upper lobe, middle lobe and lower lobe. 00:03:40.000 --> 00:03:45.000 And the left one only has two lobes, that's the first kind of a big difference. 00:03:45.000 --> 00:03:53.000 And the other difference is that you actually have this thing in the middle that we call a cardiac notch. 00:03:53.000 --> 00:03:57.000 This thing right here, this is called the cardiac notch. 00:03:57.000 --> 00:04:03.000 And the reason we call it that is that it's a little spot that gets formed 00:04:03.000 --> 00:04:07.000 because the heart is literally kind of peeking out here. 00:04:07.000 --> 00:04:11.000 And as a result it's kind of makes a notch in the lung where it develops. 00:04:11.000 --> 00:04:15.000 So the heart takes a little space here, this is the heart. 00:04:15.000 --> 00:04:22.000 And as a result, it takes or makes that notch. So this is our heart space there. 00:04:22.000 --> 00:04:27.000 So on the other side you've got of course your two lobes, your upper and lower lobes. 00:04:27.000 --> 00:04:31.000 And these are exclusive, you see a lung that's kind of sitting by itself. 00:04:31.000 --> 00:04:36.000 And you want to figure out whether it's the left lung or the right lung, 00:04:36.000 --> 00:04:40.000 you can look for the lobes, the number of lobes, or you can look for that cardiac notch. 00:04:40.000 --> 00:04:45.000 Now around here, around these lungs, you've got ribs. 00:04:45.000 --> 00:04:52.000 You've got ribs here and between the ribs you've got rib muscles and of course on both sides. 00:04:52.000 --> 00:04:59.000 And below the lungs and below the heart, you've got a muscle, a big muscle. 00:04:59.000 --> 00:05:05.000 Actually it's gonna come through here, I'm just gonna kind of go through the word heart, 00:05:05.000 --> 00:05:08.000 and it basically becomes the floor. 00:05:08.000 --> 00:05:14.000 So the heart and the two lungs sit on this floor that made up of this muscle 00:05:14.000 --> 00:05:21.000 and this muscle is the diaphragm muscle. So this diaphragm muscle makes up the floor; 00:05:21.000 --> 00:05:26.000 the ribs make up the walls. So what do we have? 00:05:26.000 --> 00:05:32.000 We have basically a room, we have a giant room with walls and the floor. 00:05:32.000 --> 00:05:36.000 And this entire room we actually call the thorax. 00:05:36.000 --> 00:05:40.000 So within this room then you have your two lungs and your heart. 00:05:40.000 --> 00:05:46.000 So, so far so good, but I haven't done a very nice job of actually showing you where the air goes. 00:05:46.000 --> 00:05:51.000 I just kind of pointed that it goes to the two lungs, we don't have to get to see where it goes after that. 00:05:51.000 --> 00:05:53.000 So let me actually, I'm gonna erase a lot of these. 00:05:53.000 --> 00:05:59.000 I’m gonna reveal to you what it would look like. If you could slip on some X-ray glasses 00:05:59.000 --> 00:06:03.000 and look into your two lungs, this is kind of what it would look like. 00:06:03.000 --> 00:06:11.000 You've got all these interesting architecture and the easiest way to kind of think about this, 00:06:11.000 --> 00:06:14.000 probably the simplest way to think about this, is to imagine a tree, 00:06:14.000 --> 00:06:19.000 to imagine a tree, and that tree has been flipped upside down, 00:06:19.000 --> 00:06:24.000 so you've got all these branches of that tree and they are branching and branching. 00:06:24.000 --> 00:06:31.000 And if you flip this tree upside down, you start seeing that it looks a lot like what we have in our lungs. 00:06:31.000 --> 00:06:37.000 Our lungs basically look like a flipped up or a flipped upside down tree and we even call that, 00:06:37.000 --> 00:06:42.000 we even call this entire structure, we call it a bronchial tree. 00:06:42.000 --> 00:06:47.000 So when you look at the lungs and they look kind of messier and complicated. 00:06:47.000 --> 00:06:52.000 Just think of them as an upside down bronchial tree and all of a sudden 00:06:52.000 --> 00:06:57.000 it'll look much simpler with basically in the middle you've got this nice trunk, 00:06:57.000 --> 00:07:01.000 this is our trunk, and then it's kind of branching from there. 00:07:01.000 --> 00:07:06.000 So air goes down this main trunk, this trachea, and they kind of start splitting up. 00:07:06.000 --> 00:07:12.000 And each of this kind of colored regions, the green region and the purple region serve a different lobe. 00:07:12.000 --> 00:07:18.000 So this green region serves the lower lobe down here, the purple serves the upper lobe. 00:07:18.000 --> 00:07:23.000 And on this side, you've got an upper, a middle and a lower lobe. 00:07:23.000 --> 00:07:25.000 Now I know it looks a little bit strange because 00:07:25.000 --> 00:07:30.000 you’ve got some green branches in what should be the middle lobe like right here; 00:07:30.000 --> 00:07:34.000 you've got some orange branches in what looks like the upper lobe like right there. 00:07:34.000 --> 00:07:39.000 But what you have to remember, this is kind of tricky, just try to play it in you head, 00:07:39.000 --> 00:07:45.000 what you have to remember is that, what you have is basically a three dimensional lung. 00:07:45.000 --> 00:07:48.000 So you have to imagine that we are literally looking at the front side, 00:07:48.000 --> 00:07:52.000 but of course that middle lobe does go back. 00:07:52.000 --> 00:07:57.000 And if you went back then you'd make perfect sense why the orange branches are where they are at. 00:07:57.000 --> 00:08:01.000 Now let me continue the air journey because I wanna make sure we finish it off. 00:08:01.000 --> 00:08:05.000 So let's say we take a little branch like that, we expand it. 00:08:05.000 --> 00:08:09.000 We keep zooming into it, zooming into it, zooming into it, 00:08:09.000 --> 00:08:12.000 until it's microscopic, you cant see it with your eyes any more; 00:08:12.000 --> 00:08:16.000 but you could see it under a microscope. It would look like this. 00:08:16.000 --> 00:08:21.000 It would basically in a microscope, it would look like a bunch of little sacs like these. 00:08:21.000 --> 00:08:27.000 And these sacs, we call these alveoli. Alveoli. 00:08:27.000 --> 00:08:30.000 And the air, it actually kind of runs into the alveoli. 00:08:30.000 --> 00:08:34.000 It has a dead end and then it comes back around. 00:08:34.000 --> 00:08:37.000 And then you breathe it out. So that's how breathing works. 00:08:37.000 --> 00:08:42.000 The air goes all the way from the mouth down to the alveoli, takes a U-turn and it goes back out. 00:08:42.000 --> 00:08:49.000 But before it does that, before it leaves- Very close to the alveoli is blood. 00:08:49.000 --> 00:08:55.000 Let's say blood is coming this way and going that way, and what will happen is that, 00:08:55.000 --> 00:08:58.000 actually out of the or into the blood, let's do that first. 00:08:58.000 --> 00:09:05.000 We've got oxygen, oxygen will actually go into the blood, and out of the blood will be waste. 00:09:05.000 --> 00:09:09.000 So you'll have some carbon dioxide waste that your cells have been making. 00:09:09.000 --> 00:09:14.000 And that waste actually then gets thrown back into the alveoli. 00:09:14.000 --> 00:09:18.000 So now you can see how oxygen gets from the outside world, 00:09:18.000 --> 00:09:21.000 gets breathed into the lungs when you inhale, 00:09:21.000 --> 00:09:25.000 gets down into the alveoli, exchanges with the blood; 00:09:25.000 --> 00:09:28.000 and then you exhale and let all that carbon dioxide out.