| 00:03 | All right, y'all. Um Today got a lot of ground to |
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| 00:06 | We're gonna be trying to play a bit of catch up. Uh When |
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| 00:09 | left on Thursday, it was right. Uh We, we were |
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| 00:14 | about, we were talking about uh in the capillaries, we have fluid |
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| 00:18 | leaves, the capillaries joins up and with the interstitial fluid and then rejoins |
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| 00:25 | with, with the fluid of the with the plasma. All right. |
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| 00:28 | in this process, about 20 liters moved, but of those 20 liters |
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| 00:33 | about a liter of that is still in the interstitial space. And if |
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| 00:38 | can imagine if your blood is about liters, roughly, it wouldn't take |
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| 00:42 | long before your blood would turn into and it would move. So, |
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| 00:47 | there needs to be a mechanism to that fluid back to uh the, |
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| 00:53 | capillaries into the bloodstream. So, purpose of the or the structure that |
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| 00:57 | gonna look at here is the All right. So the lymphatics are |
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| 01:01 | with uh the cardiovascular because of that reason. This is the point where |
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| 01:06 | returns back. But it has other which we'll just kind of point out |
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| 01:09 | of in a superficial way to hey, this is also going |
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| 01:13 | But what we're looking at here is looking at the structure of the |
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| 01:16 | So it's this, it's this network vessels that begin with what are called |
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| 01:21 | ended capillaries. All right. These the initial lymphatics. So a blunt |
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| 01:26 | capillary would be like my finger, finger is blunt. Thank you. |
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| 01:31 | what we're looking for. That's where starts. All right. And what's |
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| 01:35 | about these capillaries is that their structure different. So remember when we |
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| 01:38 | when we were describing the endothelium of , we said it was kind of |
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| 01:41 | this. So there's like a point contact and there's a type, a |
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| 01:45 | type junction, remember that. So kind of like this. This would |
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| 01:48 | a better way to see that, . So the cells are aligned like |
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| 01:52 | . But in the initial emphatic, not like that. Instead, the |
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| 01:57 | have uh these endothelial cells that overlap other like shingles. All right. |
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| 02:03 | it serves two purposes. First, way we drive fluid into the initial |
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| 02:08 | is simply by the pressure in the fluid. All right. And so |
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| 02:11 | can imagine out here this is the space, right? And so that |
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| 02:16 | space, if I have pressure press the one, right, what |
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| 02:22 | it opens up fluid can flow and it again. So everyone can see |
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| 02:26 | , you see the saw that over . Ok. So what we have |
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| 02:30 | is we have a valve system that created, right? So just simply |
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| 02:34 | pressure outside that lymphatic vessel allows for fluid to drive it. But here's |
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| 02:38 | cool thing when the pressure inside the lymphatic gets big, look what |
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| 02:44 | it can't open. And so we that fluid inside that initial lymphatic. |
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| 02:48 | so now that pressure inside the additional drives the fluid forward in the lymphatic |
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| 02:54 | . And so those initial capillaries which embedded in the, in the capillaries |
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| 02:59 | the blood or the vasculature, they're in the same location. So |
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| 03:02 | that fluid leaking out immediately goes back that into that space. All |
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| 03:08 | then the initial lymphatics turn into larger . These are the collecting lymphatics. |
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| 03:12 | very similar to the small veins. actually have one way valves. So |
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| 03:15 | fluid flows in one direction towards the instead of away from the heart. |
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| 03:20 | then that final level of lymphatic is going to be the large lymph |
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| 03:24 | These drain into the right and left vein respectively. And it's actually kind |
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| 03:29 | weird when you do the anatomy, learn that the one on the right |
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| 03:33 | only drains like the upper right arm this portion of the thoracic cavity. |
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| 03:38 | then the left one is responsible for rest of your body, you don't |
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| 03:42 | to know that. It's just weird when you see that. All |
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| 03:45 | So again, what I want to here is I want to emphasize, |
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| 03:48 | want to emphasize flow. All So pressure is driving the flu the |
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| 03:55 | . So if the pressure is greater here, it opens up fluid flows |
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| 03:59 | when the pressure becomes greater on the , it closes that, that pseudo |
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| 04:04 | , that space. So pressure now driving fluid away from the initial lymphatic |
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| 04:09 | the collecting lymphatic, ultimately to the uh lymphatics through those uh those um |
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| 04:14 | valves. And because this is fluid stuff in it, the stuff in |
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| 04:20 | fluid follows the fluid. All So what do we catch there? |
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| 04:26 | , if there are escaped proteins from plasma, the escaped proteins get |
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| 04:30 | If you skin your knee and bacteria into that space and now are creepy |
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| 04:35 | around your body, they're going to with the fluid. That's the interstitial |
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| 04:40 | and they'll get caught up in the lymphatics and they'll think it's like a |
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| 04:44 | little river ride like. All Yeah. Here we are, we're |
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| 04:46 | going to move and go with the and they move along and so we |
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| 04:50 | trap debris and plasma proteins and all of stuff in the initial lymphatics and |
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| 04:56 | directing it towards the heart. But there's more to the lymphatics than just |
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| 05:02 | fluid, it's also a surveillance uh or organ that is responsible for, |
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| 05:08 | plays a role in defense against All right now, just to point |
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| 05:15 | there's no pump, this is all , just like the flow in and |
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| 05:18 | of the capillaries is all passive, ? What drove fluid out of the |
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| 05:23 | , capillary pressure? What drove fluid the capillaries, interstitial fluid pressure and |
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| 05:30 | change between those two spots. That's we were talking about on Thursday. |
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| 05:34 | right. So just like your there's some extra help. So you'll |
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| 05:42 | uh vasomotion by the nearby arteries. , when the arteries are expanding and |
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| 05:46 | , they're pushing up against the lymphatics helps to push stuff. Um skeletal |
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| 05:50 | contraction, there's also some smooth muscle uh activity as well. That's kind |
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| 05:55 | just massaging, but it's not actually . It's just just generic, smooth |
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| 06:01 | . So this is ultimately what the do. So it accounts for that |
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| 06:07 | or two. Well, I have 2 to 4 liters per day, |
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| 06:10 | books, different things. So I your book talks about there being about |
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| 06:13 | 2 to 4 liter uh loss of . So it's just taking that fluid |
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| 06:17 | you lost into your interstitial space and it back into circulation. So that's |
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| 06:23 | one thing that it does. We spend a lot of time. In |
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| 06:27 | , we spend no time talking about immune system, but you're familiar with |
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| 06:31 | nodes? Have you ever been sick said my glands are swollen, like |
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| 06:33 | glands are swollen. Have you ever that? Right. Those are lymph |
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| 06:37 | , all right. And they sit this path along the pathway of the |
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| 06:42 | lymphatics. And so what happens is as the fluid flows, it flows |
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| 06:46 | a lymph node and inside the lymph are your immune cells and your immune |
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| 06:50 | are sitting there surveilling everything that passes . So when you're sick, what |
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| 06:55 | is you typically your B cells start really, really quickly so that you |
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| 06:58 | create an army of cells to fight . So what's gonna happen to |
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| 07:02 | Lymph node gets big and so that's going on. That's why they |
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| 07:07 | my glands are swollen. Those aren't salivary glands. Those are your lymph |
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| 07:11 | . All right, fats have to transported through the lymphatics. When you |
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| 07:16 | fats, they're packaged with other And so they cannot be transported across |
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| 07:22 | cell membrane like glucose can. So get packaged up and put into vesicles |
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| 07:27 | then they get released out in the space. And then those get picked |
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| 07:31 | through the initial lymphatics in the digestive and then are circulated through your |
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| 07:36 | We call those lymphatics around the digestive , the lacteals, lacteals because the |
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| 07:44 | in those is white, looks like . Why would it be white? |
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| 07:49 | color's fat? Fat is white? why it's not actually milk. It's |
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| 07:53 | white because there's fat that's in All right. And then of |
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| 07:57 | I mentioned also the last thing which proteins that escape out through the |
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| 08:02 | For whatever reason, if they over or whatever, this is the way |
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| 08:05 | you can turn plasma proteins back to the blood back to the plasma. |
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| 08:12 | it has multiple functions and this is the generic list. So that was |
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| 08:20 | wrap up lymphatics. And, and last thing I want to talk about |
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| 08:23 | has to do with the cardiovascular If you can just stop me, |
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| 08:27 | there's ever a question, just stop because I'm going fast today. You |
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| 08:31 | to see me pre-covid. All I talk really fast. All |
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| 08:37 | So the last thing has to do how do we accomplish arterial resistance? |
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| 08:41 | what is the things that creates arterial ? So, arterial remember is it's |
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| 08:45 | bitsy tiny arteries and so it can done locally or we can use sympathetic |
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| 08:51 | , which we already kind of talked a little bit or we have hormones |
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| 08:54 | can have this influence. And so we talk about local control, what |
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| 08:57 | really doing is basically saying, there's a metabolic need and the cells |
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| 09:01 | are in that area are going to the arterials whether to dilate or constrict |
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| 09:06 | upon that need. All right. there is two different aspects that are |
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| 09:10 | to play a role in this, is both going to be the Perrin |
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| 09:12 | . So, signaling molecules as well myogenic controls, which we'll go into |
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| 09:16 | little bit of detail here in just second. Sympathetic is simply just neural |
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| 09:21 | to make sure blood's going where it to go. Lastly, it is |
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| 09:24 | be the hormones. So we're gonna about the catecholamines. We'll also talk |
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| 09:27 | little bit about uh how we're regulating through the kidney. So it's kind |
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| 09:31 | our introduction to the kidney and blood . But when we come back to |
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| 09:35 | kidney, we're going to spend more talking about the specifics of those particular |
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| 09:42 | . So there's a lot of words here and it looks very, very |
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| 09:44 | . It's not so hard. in terms of local control, we |
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| 09:48 | active hyperemia, active hyperemia, just says when I lack oxygen, I |
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| 09:53 | oxygen. So vasodilate. So how I know I need oxygen? |
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| 09:58 | measuring actual oxygen is a really bad . What you want to do is |
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| 10:02 | want to measure metabolic activity of the . So how do you know your |
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| 10:05 | are being metabolically active? Do they co2? So we're looking for things |
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| 10:12 | are a result of an increase in activity. So we're going to be |
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| 10:16 | carbon dioxide levels. We're gonna be at ph we're gonna be looking at |
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| 10:19 | and these all have an effect on , our basically statements of, |
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| 10:24 | we are going through increased metabolic meaning we're burning through oxygen and so |
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| 10:30 | need more oxygen delivered so we can doing our activity. So notice it's |
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| 10:34 | the front end, it's the back that you're measuring. And that's something |
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| 10:37 | should just go right now. Just of put in your brain because we're |
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| 10:40 | be dealing with this over and over over again. All right. So |
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| 10:44 | gonna happen is, is these things gonna be signals from the cell to |
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| 10:49 | , hey, let's dilate reactive hyperemia a little more interesting. Um I |
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| 10:54 | to be able to do this a more fun. Um I don't have |
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| 10:58 | good in here to do this Um, let me see. I'm |
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| 11:03 | see if I actually have a rubber . Go into the Mary Poppins |
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| 11:06 | We'll find out. Nope. No band you don't need to get. |
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| 11:16 | , do you have a rubber Was that what you're reaching? Reaching |
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| 11:19 | ? If you don't have one? OK. I'll, I'll just, |
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| 11:22 | just steal this real quick. Uh oh yeah, that'll be great. |
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| 11:26 | watch my finger fall, fall We're gonna, we're gonna watch my |
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| 11:30 | follow up. This is really OK. Is this allowed to |
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| 11:35 | OK. All right. I'm just make sure OK. Ever did this |
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| 11:41 | you're a kid? Take like a band, put it on there. |
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| 11:44 | right. I'm gonna go ahead and my finger while I'm talking. So |
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| 11:47 | can imagine. I got a whole of cells that are going on that |
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| 11:49 | in here that are in desperate need oxygen. Right. I'm sitting here |
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| 11:53 | my fingers so the muscles are working hard. They're burning through their oxygen |
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| 11:57 | up that carbon dioxide. But what I done is I've occluded the flow |
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| 12:00 | blood by wrapping this rubber band Right. I didn't do it very |
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| 12:04 | this time. Normally I can get nice and purple but not like that |
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| 12:08 | , like like more of a maroon . All right. And so what |
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| 12:12 | doing is those cells are now starting get a little desperate and they start |
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| 12:15 | out that signal. Hey, look all this carbon dioxide we've made, |
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| 12:18 | need oxygen. So please will you the blood vessels are going? |
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| 12:22 | Ok, I'm dilating but no blood's . Is it? So what's happening |
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| 12:28 | , is now the cells are gonna more and more desperate and they start |
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| 12:31 | out stronger and stronger signals. And like telling the blood vessels, |
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| 12:34 | please, please, we are in need and they keep vasodilating, vasodilating |
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| 12:39 | does not come. And you can the cells are gonna start getting really |
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| 12:42 | and they're gonna start dying soon. , not soon, like maybe in |
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| 12:46 | hours. But you know, just in terms of like how that cell |
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| 12:51 | there is blood still getting in But you can kind of see, |
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| 12:53 | mean, my finger is kind of purple, right? Used to make |
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| 12:56 | really nervous when I did this. guys don't seem particularly concerned just |
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| 13:02 | Thank you for considering my welfare. right, but what will happen |
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| 13:06 | is over time, you know, keep dilating, keep dialing, nothing's |
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| 13:10 | . And then eventually what will happen I'll get my relief. Thank you |
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| 13:14 | much. Uh See, look at , you know, for those who |
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| 13:19 | interested, see, I was, was o including the flow of |
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| 13:22 | right? See, look at Isn't that cool? Right? And |
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| 13:26 | all of a sudden we got blood in, they got all the blood |
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| 13:29 | it needs, all the oxygen needs the glucose it needs. And so |
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| 13:32 | happening? Is it like? we got everything. So we're gonna |
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| 13:35 | ahead and just relax. No, blood vessels are gonna remain open because |
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| 13:40 | do not know when blood is gonna flowing again. In other words, |
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| 13:44 | are reacting to uh that um that that they've received or sorry, you |
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| 13:52 | that it's basically, hey, we're . We don't know when it's gonna |
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| 13:55 | . So we're just gonna overwash, gonna keep flowing in blood and we're |
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| 13:59 | keep this dilated until we're 100% certain happy. So it's not just |
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| 14:05 | a simple. Oh OK. You what you needed. Now, we're |
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| 14:08 | move on to the next section, maintaining it. It's gonna be like |
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| 14:11 | for a little while. All Last. Yeah. Um, it's |
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| 14:17 | , it's gonna be depend upon the and again, it's, it's |
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| 14:20 | it's, the difference is in seconds minutes. How about that? |
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| 14:24 | So, like when, when you're with active hyperemia, that would be |
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| 14:29 | in seconds or milliseconds, whereas reactive be seconds to minutes. Like, |
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| 14:35 | , we're just gonna allow this area wash over in, in, in |
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| 14:39 | so that the cells can get exactly they need. We can make sure |
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| 14:42 | everyone is caught up and is completely in. Last is a myogenic |
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| 14:48 | And simply what this says is, , um we're gonna make uh sure |
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| 14:53 | the blood is flowing in a more less constant fashion despite normal changes. |
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| 14:58 | you've heard of, of uh for , um I'm now blanking on the |
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| 15:05 | uh the Hypo Hypo osmotic pressure, ? When you sit down and you |
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| 15:10 | up and the blood pressure drops, not dropping, right? Blood pressure |
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| 15:14 | not dropping, your blood pressure is same. It just hasn't risen to |
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| 15:17 | your need when you stand up. right. So that's an example of |
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| 15:22 | activity is that the blood vessels go there's a drop in pressure or, |
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| 15:28 | the the amount of pressure inside this should be this, but instead it's |
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| 15:32 | . So what we're gonna do is going to increase or decrease pressure to |
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| 15:37 | what the body is supposed to be . All right. So, um |
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| 15:43 | will be vasoconstriction or vasodilation. if the blood vessels have higher pressure |
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| 15:48 | them, they're gonna start feeling that . So what are they gonna wanna |
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| 15:53 | ? They want to relax to reduce pressure, right. Oh The pressures |
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| 15:57 | inside this vessel. I'm no longer the same pressure that I want to |
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| 16:01 | . So what do I wanna I wanna constrict. So that would |
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| 16:04 | auto regulation. They are responding to pressure that they're receiving in that vessel |
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| 16:10 | than being told whether or not to or decrease their pressure. Yeah. |
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| 16:20 | an inclusion would be to literally clamp close, not through normal means the |
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| 16:25 | of blood, right? So like I did there is I wrapped it |
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| 16:29 | and, and I prevented blood flowing the end of my finger, |
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| 16:33 | Think about the single mammon oer. you see how I said that without |
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| 16:36 | about it, if I think about , I'm not gonna be able to |
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| 16:39 | it ever again. All right. that was the same thing. What |
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| 16:41 | we do is we occ include the of blood through that artery and then |
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| 16:45 | relax it. So that would that's what the occlusion is. Another |
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| 16:48 | is you could put a, you , like a bolus in it. |
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| 16:51 | that's what a stroke would be, be an occlusion. So, just |
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| 16:55 | , uh, i impeding the flow blood in an unnatural way. All |
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| 17:00 | . Now, there are the local . What do we have here? |
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| 17:03 | Nitric oxide. It's a vasodilator, . It's released by the endothelium is |
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| 17:08 | vasoconstrictor. All right. That's all gonna need to know if you have |
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| 17:12 | know these at all is just which the dilator, which one's the |
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| 17:16 | All right. So these are released the endothelial cells in response to. |
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| 17:21 | you'd release nitric oxide in response to so that you get vasodilation in |
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| 17:27 | you would uh what you do is release in in response to a dilated |
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| 17:32 | that needs to produce more pressure. also has an effect. We mentioned |
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| 17:37 | already that's a by product of metabolic . And um and sheer force |
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| 17:43 | that's basically the pressure against the walls the cell, autonomic control. We've |
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| 17:49 | about this already. I just, am going to point this out. |
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| 17:54 | again, we are dealing primarily with . There's uh for the most part |
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| 17:59 | , I think there's like one system has parasympathetic, but everywhere else, |
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| 18:02 | all sympathetically controlled. So if I sympathetic activity, I'm going to increase |
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| 18:09 | . If I decrease sympathetic activity, gonna uh cause vasodilation. So there |
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| 18:14 | a tonic level of stimulation and that's this is trying to show you up |
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| 18:18 | at the top that's the tonic So it's always firing at a specific |
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| 18:23 | . And what I do if I rate, I'm getting the vaso |
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| 18:26 | If I decrease it, I'm getting . All right. Um S I'm |
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| 18:39 | ignore the actual uh uh types a , alpha one so on and so |
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| 18:45 | in terms of arterial resistance when it to hormonal control. Again, these |
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| 18:50 | the catecholamines, epi and nor epi generally speaking, uh alpha ones which |
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| 18:55 | everywhere, these are gonna be causing . Beta two's cause dilation. |
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| 19:01 | this is why I'm trying to avoid because this becomes a little confusing. |
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| 19:05 | right, when my heart beats blood flows faster, right? Why |
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| 19:11 | blood flow faster? Well, the is beating more frequently. But the |
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| 19:15 | thing that I'm doing is I'm constricting blood vessel, I'm constricting the |
|
| 19:19 | When you think of constriction, what you think of? What's, what |
|
| 19:22 | the word that would go with Flow resistance or pressure resistance is what |
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| 19:29 | right. So if I constrict, gonna increase resistance, right? But |
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| 19:34 | , I'm increasing resistance, but I'm increasing the flow rate. Blood is |
|
| 19:39 | quickly through those tissues to get to they need to go. Now, |
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| 19:43 | the weird part in skeletal muscle. where you'll see beta twos, |
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| 19:48 | So generally everywhere you're going to have alpha receptors that are constricting to increase |
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| 19:54 | speed at which the blood is getting a place and then what happens is |
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| 19:58 | get into those tissues, like the and they dilate. So what would |
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| 20:03 | to the flow rate is decreasing? . So you can imagine it's like |
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| 20:09 | to get the blood to where it to go and then it's slowing down |
|
| 20:12 | that it can go through exchange. then as you get back out of |
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| 20:16 | capillaries again, constriction get right back the heart, get pumped back |
|
| 20:20 | slow down again. All right. you can see here that when it |
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| 20:28 | to the catecholamines, that some catecholamine the catecholamine will act differently in different |
|
| 20:35 | is what I'm trying to get at right. They accomplish the right goal |
|
| 20:40 | . I'm speeding things up through but then I'm slowing things down to |
|
| 20:44 | so I can get exchange. That's weird thing. So it's not like |
|
| 20:48 | everywhere. All right, you do dilation. The two hormones I want |
|
| 20:55 | to be interested in right now. vas suppressant also known as anti diuretic |
|
| 20:58 | or a DH. Uh The way can think about this is antidiuresis anti |
|
| 21:04 | against diuresis is peeing. So it's peeing hormone now, is it making |
|
| 21:11 | not pee? No, what it's is it's not allowing you to make |
|
| 21:17 | . All right. And so the that you would normally pee out right |
|
| 21:21 | form urine with stays in the So you be are creating a |
|
| 21:27 | uh you're always creating urine at a rate. But how much water you |
|
| 21:31 | in that urine is gonna be dependent the presence of a DH. All |
|
| 21:35 | . So here, what a DH doing is it is um uh basically |
|
| 21:40 | water balance by promoting water retention. right. So that's the antidiuresis |
|
| 21:45 | But the other thing that it does it plays vasoconstrictor. So both of |
|
| 21:49 | things together are increasing pressure, If water doesn't leave my body, |
|
| 21:55 | pressure stays high, right? If constrict a blood vessel, what happens |
|
| 22:03 | the pressure it goes up? So two things are being accomplished through a |
|
| 22:08 | , the other one here is angiotensin . Why it's not angiotensin one? |
|
| 22:13 | a long process, it starts off angiotensinogen goes through A T one becomes |
|
| 22:18 | T two and then we don't talk it any further after that, but |
|
| 22:21 | becomes A T three and A T . We don't talk about it. |
|
| 22:24 | like Bruno. All right, because primarily don't know what it does after |
|
| 22:31 | . But what A T two is also a vasoconstrictor. All |
|
| 22:36 | Angio refers itself to the cardiovascular So usually heart but also some of |
|
| 22:42 | vasculature, tension is two words jammed , tension and protein. So it's |
|
| 22:49 | increaser of pressure. Now, what does, it also regulates water salt |
|
| 22:54 | . Basically, what it does is promotes water retention. So, that's |
|
| 23:00 | we're doing two different ways. Con constriction and keeping water in the body |
|
| 23:06 | of peeing it out. Those are jobs. All right. So that |
|
| 23:10 | 20 minutes to get through the last bit of that lecture from Thursday. |
|
| 23:15 | , my goodness. All right. you have a question? Go ahead |
|
| 23:18 | ask away. Uh huh. Different though. Yeah. We'll get to |
|
| 23:27 | house when we talk about the All right. So I'll just, |
|
| 23:31 | give you a preview. Kidney has hormones. They all start with the |
|
| 23:34 | A, three of them. Do same thing. One does not. |
|
| 23:38 | this is where we're gonna fall back Sesame Street. One of these things |
|
| 23:42 | not like the others. Yeah. we go. Yeah. OK. |
|
| 23:48 | , but I don't wanna, I wanna get into it now, |
|
| 23:50 | Yeah. So ready for respiratory Ok. You spent most of your |
|
| 23:57 | career learning about cellular respiration, cellular is just half the story. All |
|
| 24:03 | , respiration is getting air into the and then moving it to the |
|
| 24:08 | Not all our cells are in direct with the external environment. So they |
|
| 24:12 | all get the air that way. really the purpose of the respiratory system |
|
| 24:15 | conjunction with the cardiovascular system is to all the cells to the surface |
|
| 24:22 | right? So that they can do gas exchange. All right, we're |
|
| 24:26 | gonna talk about cell respiration here, gonna be talking about the process of |
|
| 24:31 | the air from the external environment into body and then to those cells and |
|
| 24:36 | we'll let uh, cell biology and talk about the rest. Ok. |
|
| 24:41 | right. There are some non respiratory of the respiratory system. We've talked |
|
| 24:49 | the nose being an organ of We haven't talked about vocalization, but |
|
| 24:53 | how you make sounds is through moving , in and out through the |
|
| 24:57 | Um We lose heat and uh uh through breath, water escape or uh |
|
| 25:05 | passed into the lungs. So I this bottom picture is very strange for |
|
| 25:09 | of us. For those of you ever been around cold weather, then |
|
| 25:13 | , you're familiar with this, starting October. All right. But for |
|
| 25:17 | rest of us, maybe January, . All right. Uh we process |
|
| 25:23 | . So in the processing, that's warming, humidifying the air, filtering |
|
| 25:27 | air. Uh the lungs play an role in defending against inhaled foreign |
|
| 25:32 | Um, in terms of the uh , we're gonna enhance venous return. |
|
| 25:37 | talked about the respiratory pump, we about the blood reservoir wire for the |
|
| 25:41 | ventricle. Um So the the circulation being pulled into that area. Um |
|
| 25:48 | also going to remove materials through pulmonary . So when materials go into the |
|
| 25:55 | , things are being passed into the that will be removed outward. And |
|
| 25:59 | thing we're not gonna talk about at . Although we probably should, but |
|
| 26:02 | just only have 25 lectures to give this or 26 lectures for the |
|
| 26:07 | So, acid based balance. And this is just another major thing. |
|
| 26:11 | a, uh, you go to book, I guarantee you there's a |
|
| 26:14 | chapter on acid based balance. All . So there are a lot of |
|
| 26:17 | things going on. There's a lot anatomy here too. Do you guys |
|
| 26:21 | where your larynx is? It's it's this thing right here, |
|
| 26:25 | No, it's, it's this thing sits for, for men. It |
|
| 26:28 | out and prominent. It's what gives our deep voice is our voice |
|
| 26:32 | That boundary. The larynx is the between the upper respiratory system and the |
|
| 26:37 | respiratory system. All right. So you know where your larynx is and |
|
| 26:41 | if you can't feel it, it's prominent, just hit the middle of |
|
| 26:44 | throat and you'll find it. It's hard. Ok. It's the thing |
|
| 26:47 | makes the funny noise. So air gonna enter in, through the nose |
|
| 26:51 | the mouth. It does enter through mouth. It doesn't necessarily, it's |
|
| 26:54 | necessarily supposed to. All right, passes down through the pharynx, pharynx |
|
| 26:59 | this fancy word for throat. All . And then to the larynx and |
|
| 27:03 | once you get past the larynx, gonna move down through the trachea and |
|
| 27:07 | the bronchi. Um, so I'm showing you a picture of the larynx |
|
| 27:11 | . It's through voice box. You see what it does. It open |
|
| 27:14 | closes. These are basically very, tight structures that you can change |
|
| 27:19 | their tightness. And so that's why able to get those unique vibrations this |
|
| 27:24 | the elastic tissue. When you you're gonna close that off because you |
|
| 27:29 | your no, no, no, milkshakes, no coffee into the |
|
| 27:34 | That's bad. Tacos, especially right? So, all right. |
|
| 27:39 | when you get down to the bronchial , these are the structures that are |
|
| 27:43 | inside the lungs. So we start the trachea, the trachea are going |
|
| 27:47 | divide, become bronchi, the bronchi and they divide and they divide and |
|
| 27:51 | divide and you get down to the tiny bits and you have bronchioles. |
|
| 27:55 | right. There are two different types bronchioles when you get down to the |
|
| 27:58 | end. All right. So, , bronchioles is defined as being smaller |
|
| 28:02 | a millimeter in diameter. All So what you've done here is you |
|
| 28:06 | the terminal bronchioles. This is what refer to as a portion of the |
|
| 28:09 | zone. So, conduction is where is no gas exchange. All you're |
|
| 28:14 | is a passage way between two So I'm just gonna ask you a |
|
| 28:17 | simple question. Is an artery, conductor or an exchanger. What do |
|
| 28:22 | think I'm moving into a different I'm jump back is an artery, |
|
| 28:25 | conductor or an exchanger? What's a ? What's a vein good? So |
|
| 28:32 | already understand this concept. So, we're saying here is there is a |
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| 28:35 | of the lungs that plays no role exchange. It's just a passage way |
|
| 28:40 | get down to where exchange takes All right, that's where the respiratory |
|
| 28:44 | come into play is that first segment the respiratory zone. So there are |
|
| 28:49 | bronchioles that play a role in It's not the terminal end, but |
|
| 28:54 | is a portion of the tree that ex changes from uh conduction to |
|
| 29:01 | And I love your book because no book I've ever seen shows you that |
|
| 29:06 | somebody figured this out, somebody who this was important went down and dissected |
|
| 29:12 | and kept dissecting it down to got many branches and there's 24 generations in |
|
| 29:19 | wild. What does that mean? generations, branch, branch, |
|
| 29:23 | branch, branch, branch, keep until you do that 24 times, |
|
| 29:29 | ? And you're down to these itsy teeny tiny structures. And within all |
|
| 29:34 | , look at this, that's terminal then now you're in, that's all |
|
| 29:39 | conducting zone. And then that means is all exchange zone. And what |
|
| 29:44 | getting down to is not to those bronchioles. That's just the first |
|
| 29:49 | What you're working down to are the . This is where we want to |
|
| 29:54 | our time. So this is the zone in a nutshell. Well, |
|
| 29:59 | a cartoon picture, I guess. right. And so what you have |
|
| 30:03 | , they're showing you uh the vasculature well in this picture. And so |
|
| 30:08 | we have here is we have the , here's the terminal bronchial, they're |
|
| 30:11 | to say, but down here we're get to the point where we're now |
|
| 30:15 | exchange to take place. And so see ducks. So ducks are simply |
|
| 30:20 | pass that are going in between the alveoli. They are similar to the |
|
| 30:25 | way I can describe it is think a bunch of grapes, ok? |
|
| 30:29 | the alveoli are a bunch of the little stems that are connecting all |
|
| 30:32 | grapes together, those are the alveolar and then those things are connecting together |
|
| 30:36 | getting into the larger stems. You , those are the things that your |
|
| 30:40 | cut so that you didn't have to those in your lunch, right? |
|
| 30:43 | had the little tiny bunch, So that's what we're kind of looking |
|
| 30:46 | here. And then so when you down to the alveoli, that's where |
|
| 30:50 | gonna see the individual sack. So is a or actually a sack is |
|
| 30:54 | the bunch of grapes. So that's we want to do too. So |
|
| 30:57 | alveoli is where the actual exchange is place. This is where our focus |
|
| 31:00 | gonna be. But everything you see here is allowing for exchange And so |
|
| 31:06 | we've done is we've taken our lungs you can see my, my |
|
| 31:09 | my chest is basically this big, ? You know, whatever on the |
|
| 31:14 | . And you can imagine there is finite volume in there, right? |
|
| 31:17 | could probably measure that volume, But what we're doing is that volume |
|
| 31:22 | being divided up so that we can surface area. Because what we want |
|
| 31:27 | we want an increased surface area so can have greater exchange taking place. |
|
| 31:31 | , good old fixed law way back the beginning of the semester. And |
|
| 31:34 | said, you gotta remember this stuff it's gonna keep popping up and you're |
|
| 31:37 | , yeah, whatever. I'll just for the test and put it in |
|
| 31:39 | you know, said, forget I'm done with it. Fixed law |
|
| 31:42 | showing up again, increasing surface creases diffusion. And so what we |
|
| 31:47 | here is when we get down to sacks, we have about 3 to |
|
| 31:52 | million alveoli per lung. That's basically taking that volume and dividing and dividing |
|
| 31:59 | until you get down to the itsy teeny tiny structures. And in doing |
|
| 32:04 | you've increased surface area. Now, don't know how much surface area |
|
| 32:07 | Are you ready for the lie? , because I've seen this at least |
|
| 32:10 | textbooks, but we know it's not . But let's just pretend it |
|
| 32:14 | You have like a tennis court, tennis course courts worth of surface area |
|
| 32:21 | each lung. All right. That . We don't know. It's |
|
| 32:28 | it's a mathematical calculation that no one for sure. Somebody said, |
|
| 32:32 | that sounds like this. And they it in a book and now it |
|
| 32:34 | been repeated a dozen times. It's entirely accurate, but let's just pretend |
|
| 32:40 | is. All right. Look how you are. Look at your little |
|
| 32:44 | cells and now think of that space your lungs, each lung has a |
|
| 32:49 | courts worth of surface area. That's . So that's how much gas exchange |
|
| 32:55 | can do. We've increased that surface around each one of these, |
|
| 33:00 | We have uh uh blood vessels, ? So this capillary systems that's going |
|
| 33:05 | allow for the exchange to take We have elastic fibers so that when |
|
| 33:09 | stretch alveolus, it will want to back to its original shape and then |
|
| 33:13 | each of the individual alveoli themselves are and that's what they're trying to show |
|
| 33:17 | here. So they are not individual , they are interconnected. So as |
|
| 33:22 | expand one, you're not just expanding , you're expanding. All. All |
|
| 33:27 | . So it increases surface area and exchange by doing so so far. |
|
| 33:32 | you with me? OK. Let's a look inside an alveolus three cells |
|
| 33:37 | need to know about first type of . It's called a type one |
|
| 33:41 | Alveolar type one. Really, really . All right. The type one |
|
| 33:45 | makes up the surface of an Very, very boring cell. It's |
|
| 33:51 | , most abundant. And it is wall of the balloon. All |
|
| 33:57 | Second type of cell type two What does it do? Well, |
|
| 34:02 | stuck around here. I think that's it is. Yeah. No, |
|
| 34:04 | are macrophages. So, these are other things I thought were macrophages. |
|
| 34:09 | little things right there in a little represent the alveolar type two cell. |
|
| 34:12 | they do is they produce a All right, we're gonna talk about |
|
| 34:16 | at the very last part of the . But what the fact is just |
|
| 34:20 | material that coats the inside of the plays an important role to ensure that |
|
| 34:25 | alveolus doesn't collapse on itself and becomes inflatable. All right, that's, |
|
| 34:30 | the gist of it. The third is sitting there wandering around from alveoli |
|
| 34:34 | Alveoli, kind of like a cop the beach. Just kind of checking |
|
| 34:37 | out and making sure things are These are the alveolar macrophages. So |
|
| 34:42 | is a resident macrophage, but they're static. They are mobile, they're |
|
| 34:46 | moving around. You've probably heard at point in your life. Again. |
|
| 34:51 | thing I do not know if it's or not is that over the course |
|
| 34:54 | your lifespan? You'll inhale like two worth of dirt while you're breathing. |
|
| 35:00 | that true? I don't know. days it feels like it right. |
|
| 35:05 | days you know, maybe not. know, maybe if you go to |
|
| 35:08 | concert, you might feel like it's full bucket that day, you |
|
| 35:12 | but that's the idea is dust and so, you know, so that |
|
| 35:15 | feel totally gross, dust is basically skin cells and other skin things that |
|
| 35:19 | floating around in the air. So inhaling people just felt like I had |
|
| 35:25 | say that. All right, other . So you can see here here's |
|
| 35:29 | alveolus alveoli are right next to. , um this is the alveolus cis |
|
| 35:34 | here is the capillary. So we're coming in close and you can see |
|
| 35:37 | that the distance between the plasma and capillary and the air that's found inside |
|
| 35:43 | old alveolus is very, very The reason for that is because that |
|
| 35:47 | is very thin, it's about half millimeter. All right. So one |
|
| 35:51 | the reasons why pneumonia is so dangerous so deadly or it used to be |
|
| 35:56 | because pneumonia is characterized, it's not an infection, it's characterized by an |
|
| 36:02 | of fluid in the lungs. So I have 0.5 millimeters, right? |
|
| 36:08 | I can have gas exchange across that millimeter. But if I had 0.1 |
|
| 36:12 | of water, that is now a thickness of 0.2 or sorry 0.6 |
|
| 36:18 | I only increased it 20% right. still a lot because it goes back |
|
| 36:24 | fixed law because thickness matters, That's why it's so dangerous. So |
|
| 36:31 | want to regulate and make sure that doesn't happen. We want to keep |
|
| 36:34 | , that membrane nice and cheap or not cheap, but uh |
|
| 36:39 | All right. Um So this is , the surface area 500 to 100 |
|
| 36:45 | uh meters squared. That's why I'm , we don't really know what the |
|
| 36:49 | is. And then in terms of much uh capacity you have in your |
|
| 36:54 | is somewhere between five and six liters air. All right, if you're |
|
| 36:59 | , less, if you're bigger now, let's talk about a |
|
| 37:07 | Yes, sir. Um you can it, right. That's one of |
|
| 37:16 | ways that, that it's done. So part of the reason that the |
|
| 37:20 | lungs would accumulate fluid is not that just shows up, right? What's |
|
| 37:25 | is, is you're getting vasodilation if is an immune response from the |
|
| 37:31 | So you get vasodilation and so when get that vasodilation fluids seep into the |
|
| 37:36 | and create that barrier, that's So, so how do we get |
|
| 37:40 | of it? The same way? basically reabsorb it back into the |
|
| 37:44 | Yeah. But as long as you're , not gonna happen. And also |
|
| 37:49 | uh if you have too much it actually sinks down low and that |
|
| 37:53 | an effect on breathing and stuff. your book talks about that. I |
|
| 37:56 | teach that because one, I don't it too. I mean, that's |
|
| 37:59 | rule. If, I don't know , I'm not gonna teach you. |
|
| 38:01 | that? Does that sound fair? . Yeah. All right. Let's |
|
| 38:06 | about the anatomy of the lung. is really, really interesting. All |
|
| 38:10 | . So, what do we have ? We talked about the bronchi |
|
| 38:13 | So, we have these airways, ? We have alveoli, we have |
|
| 38:17 | vessels, right. We saw the vessels. um there's connective tissue and |
|
| 38:22 | some smooth muscle that's wrapped around like can see here wrapped around the |
|
| 38:30 | there's no skeletal muscle and then on outside, we're gonna have serous |
|
| 38:34 | All right. So serous membrane, is the purpose of a serous |
|
| 38:40 | Friction, reduces friction, right? things that are moving. All |
|
| 38:44 | we call this cous membrane, the . All right. So how this |
|
| 38:49 | forms is you can imagine, I a, a um structure that is |
|
| 38:56 | be adhered to the inside wall of thoracic cage. All right. This |
|
| 39:01 | your thoracic cage. If you think your ribs, does it look like |
|
| 39:04 | cage? So thoracic cage, So what you have is this, |
|
| 39:09 | structure is adhered to two things. adhered to the thoracic wall and it's |
|
| 39:14 | to the developing lung on the And so what you have is you |
|
| 39:18 | a potential space between these two structures it's really a balloon. The picture |
|
| 39:22 | see every book uses is like it's like you have the balloon and |
|
| 39:26 | take another balloon and you stick it the balloon or it might be a |
|
| 39:28 | that you put in the balloon. what happens is the balloon wraps around |
|
| 39:31 | structure. And so really, that's going on in the lung as it |
|
| 39:33 | , it's surrounded by this structure that's adhered to the outside wall. And |
|
| 39:37 | what you do is you're pushing the into this thing and you're creating this |
|
| 39:42 | that is now adhered on one on the thoracic cage and on the |
|
| 39:46 | side of the lung. And so this really, really thin potential |
|
| 39:50 | All right, we have names for . Anything that's adhered to the uh |
|
| 39:55 | an organ is called the visceral So this would be the visceral |
|
| 39:58 | anything that's adhered to the, away that the, the lung or the |
|
| 40:03 | or whatever it would be referred to being parietal. So this would be |
|
| 40:07 | visceral side. That would be the . There's a viser side, there |
|
| 40:10 | the parietal. All right. why do we even care about |
|
| 40:14 | All right. Well, first I think I've told you this |
|
| 40:22 | You're made of meat, right? said that I did OK, you're |
|
| 40:28 | of meat and when you add heat meat, what happens to the |
|
| 40:31 | it cooks, right? So, about how often you breathe during a |
|
| 40:36 | . All right, your lungs are in and out, in and |
|
| 40:39 | in and out. And so they're be rubbing against the thoracic cage. |
|
| 40:43 | over time you cook that meat nice golden brown and then you'd have a |
|
| 40:47 | , stiff, hard structure because when cook meat, that's what you do |
|
| 40:53 | you cross-link the protein fibers and so get nice and hard and juicy and |
|
| 40:57 | . I don't know about lung but I'm just saying, generally |
|
| 41:00 | All right, what's another way we cook meat? But how do we |
|
| 41:04 | meat down here in Texas, particularly the summer and the spring barbecue? |
|
| 41:09 | , what's, what's barbecue smoking? it. That's exactly right. You |
|
| 41:15 | the meat, right? You're using temperature smoke and that low temperature smoke |
|
| 41:20 | going to cross link the fibers and , it's the same sort of |
|
| 41:23 | You're just cross linking. There's another to cook meat if you like |
|
| 41:27 | What are you doing? What are cooking with acids? Right. Take |
|
| 41:34 | whole bunch of acids. Drop, your meat into that. That |
|
| 41:38 | it could be steak, it could fish, it could be whatever you |
|
| 41:42 | to, right? But acid lower will also do the same thing. |
|
| 41:47 | like the proteins right now. Why I bring this up? What does |
|
| 41:53 | do? I'm talking, smoking or , whichever, whichever way you wanna |
|
| 42:00 | it. So, what's it doing your lungs? It's cooking them, |
|
| 42:05 | cross linking the proteins and we don't a lot of stuff in there. |
|
| 42:09 | have elastic fibers and we have smooth . Ok. So the purpose here |
|
| 42:16 | the first place of the serous membrane to prevent that friction. So, |
|
| 42:21 | we're breathing, we're not stiffening up hardening the lungs, that's its |
|
| 42:27 | All right, but it has another as well. All right, with |
|
| 42:33 | to the respiratory muscles, let's go over the list. What, what |
|
| 42:37 | do we have in the lungs? mentioned, we have elastic fibers. |
|
| 42:42 | mentioned trachea and bronchi, we mentioned , we got blood vessels, we |
|
| 42:46 | um smooth muscle. But do we any skeletal muscle in the lungs? |
|
| 42:55 | . All right. But can we regulate how we breathe? Can we |
|
| 42:59 | breathe in real quick? Let's all out real quick and let's shake off |
|
| 43:05 | skin to make people eat that. right. But I can't control smooth |
|
| 43:13 | . So where are my respiratory They are on the outside? They're |
|
| 43:18 | the thoracic cage, they're the So they make up the floor. |
|
| 43:22 | our respiratory muscles are external to the . And so the second role of |
|
| 43:28 | serous membrane is to attach the lungs skeletal muscles. Ok. That's its |
|
| 43:34 | goal, that's its other purpose. so by pulling, we're going to |
|
| 43:37 | to how we do this. But pulling on that cerus membrane, when |
|
| 43:40 | contract the muscles of the chest. going to happen is I pull on |
|
| 43:44 | cerus membrane and that cerus membrane is to pull on the lung and cause |
|
| 43:49 | to stretch. Ok. We might do a demonstration in class because it's |
|
| 43:55 | . OK. So we're not acting on the lung. We're acting indirectly |
|
| 44:01 | the goal here, we're acting on cer membrane. We're not acting on |
|
| 44:04 | lung tissue directly. And what we're do is we're gonna create changes in |
|
| 44:10 | . So that when we create those in volume, we're going to alter |
|
| 44:15 | . And when we alter pressure, move. Right. That's the |
|
| 44:19 | All right. So let's pause. put a pin in that. And |
|
| 44:25 | let's start talking a little bit about physics. Oh, my goodness. |
|
| 44:30 | . Uh All right, gas First off, what is atmospheric |
|
| 44:35 | atmospheric air is a mixture of We've already talked about this. What |
|
| 44:39 | air? It is first and nitrogen. It's all right. I |
|
| 44:45 | what you're thinking. Do. We use the nitrogen? No, it's |
|
| 44:49 | waste of our time and effort. it's there. It's not, it's |
|
| 44:53 | nitrogen, roughly 79 point something. right. Followed by, followed |
|
| 45:00 | followed by, who knows? it's on the list up there, |
|
| 45:04 | sure. Oh, look argon. . There it is. OK. |
|
| 45:08 | , there's more argon in the air there is carbon dioxide. So, |
|
| 45:11 | you go. All right. So is a mixture of gasses. All |
|
| 45:16 | , Dalton's law says that when you the pressure of the atmosphere of any |
|
| 45:20 | of gasses for that matter, each those pressures of the individual gasses make |
|
| 45:25 | the total pressure. All right. atmospheric air is a mixture of all |
|
| 45:30 | gasses. So if you look at atmospheric air at 7 60 millimeters of |
|
| 45:34 | and say, OK, that is pressure. And I know that uh |
|
| 45:39 | is 79% of that. I could 0.79 multiply by the 7 60. |
|
| 45:43 | I can figure out what the partial of nitrogen is in atmospheric air and |
|
| 45:48 | can do it for every single solitary that's in the air. All |
|
| 45:53 | in Houston, we have a special that's floating around. I'm not talking |
|
| 45:57 | gas. What is that special That's just always there. Humidity. |
|
| 46:04 | is humidity, water? So that a gas, you know, in |
|
| 46:10 | or that is a molecule in his form just circulate. All right. |
|
| 46:14 | you have to take into consideration all gasses that are there when you're doing |
|
| 46:18 | partial pressures. All right. Second , this is a rule that you |
|
| 46:22 | already understand gasses are gonna move down partial pressure gradients. So just the |
|
| 46:27 | rules we learned about P pressures, pressure gradients are the same thing as |
|
| 46:30 | gradient. It's just we call it pressure because we're referring specifically to that |
|
| 46:35 | gas, right. So in when I put air in my |
|
| 46:39 | the partial pressure of oxygen is greater the lungs than it is in the |
|
| 46:43 | . So, which way does oxygen go out of the lungs and into |
|
| 46:46 | blood? So it follows as partial gradient. All right, the partial |
|
| 46:51 | of carbon dioxide is greater in the in the lungs than it is in |
|
| 46:55 | lungs. So, which way does dioxide want to go out to the |
|
| 46:59 | ? And then when I breathe and it out, I'm basically moving the |
|
| 47:03 | that has undergone exchange. All But it's still just air. So |
|
| 47:08 | I'm exhaling, I'm exhaling oxygen with uh you know, but I'm also |
|
| 47:14 | more carbon dioxide. I'm just exhaling oxygen that didn't get exchanged. All |
|
| 47:20 | . Now, when you take a and you put it into a |
|
| 47:24 | it maintains or retains its partial pressure a function of the total volume, |
|
| 47:29 | is Henry's law. I didn't know had a law, but now you |
|
| 47:33 | . All right. So the more there is the greater the pressure. |
|
| 47:37 | not hard to understand. All Think of a soda, a |
|
| 47:41 | it is carbon dioxide dissolved in What happens when you uh when you |
|
| 47:47 | that carbon dioxide and you seal it , you have more carbon dioxide in |
|
| 47:50 | container and then when you pop that . What do you hear? And |
|
| 47:55 | is a carbon dioxide going from the pressure out into the environment where there's |
|
| 47:59 | pressure and then you can watch the dioxide collectively come together and those are |
|
| 48:05 | bubbles and then they work their way to the surface. All right. |
|
| 48:08 | that's just Henry's law visualized. alveolar air, the air in your |
|
| 48:16 | . All right. So we remember talking about where exchange is taking place |
|
| 48:19 | not the same thing as atmosphere All right. Now, even though |
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| 48:23 | here we have a lot of humidity here, we have more humidity. |
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| 48:27 | right. So you just gotta imagine in Houston. So we can exaggerate |
|
| 48:30 | little bit. All right. So I breathe in, what's happening |
|
| 48:34 | is there is humidity in my body that humidity is in the form of |
|
| 48:39 | that, that, that water. so when the air comes into my |
|
| 48:43 | , I'm gonna mix, mix it that humid air. And so I'm |
|
| 48:47 | water to the air now, you this, right? We can go |
|
| 48:51 | to that picture of the picture of person in the cold when I breathe |
|
| 48:54 | and out and it's cold. I see the condensation of that water as |
|
| 48:58 | leaving my body, right. So adding water to the air when it |
|
| 49:05 | in. All right. So that the partial pressures are slightly changing, |
|
| 49:10 | ? Because if I have 100% of . And I'm changing the percentiles of |
|
| 49:14 | of the things that are going then the partial pressures are changing. |
|
| 49:18 | makes sense. So if, if going in has 0% water, but |
|
| 49:23 | it comes into my lungs is now water, that means the nitrogen, |
|
| 49:27 | oxygen, the carbon dioxide, those have changed also. And thus they're |
|
| 49:32 | pressures. All right. Now, water or when air gets into my |
|
| 49:38 | , oxygen always, always, always away from the lungs. It's always |
|
| 49:43 | to escape. It doesn't matter if breathing in. Right? So if |
|
| 49:48 | breathing in air, I'm adding in air, that means I'm adding in |
|
| 49:51 | oxygen. But oxygen is still leaving lungs going into the blood. If |
|
| 49:54 | holding my breath or if I'm between , oxygen is still moving into the |
|
| 50:00 | . If I'm exhaling oxygen is moving the blood, why it's a partial |
|
| 50:06 | gradient that it is following? All . I'm not worried about the bulk |
|
| 50:10 | . I'm only concerned with oxygen. right. So it doesn't matter. |
|
| 50:14 | this, I guarantee you put a star by this. I asked this |
|
| 50:17 | every class and not everyone gets the answer I'm giving you a free two |
|
| 50:22 | on the exam. It doesn't matter you're breathing in, breathing out or |
|
| 50:26 | your breath. Oxygen moves down its gradient or partial pressure, not concentrate |
|
| 50:33 | pressure gradient. Right? And I I framed the question some of |
|
| 50:36 | the effect of you're holding the breath oxygen moving in, you know, |
|
| 50:41 | , which direction is oxygen going or like that? When you're holding your |
|
| 50:47 | , breathing in and breathing out, carbon dioxin doing the same thing? |
|
| 50:50 | always moving down, it's pressure gradient it will continue moving down its pressure |
|
| 50:55 | until what happens, equ equilibrium is what we're looking for, right? |
|
| 51:02 | it's never reached equilibrium is never Now, it could be reached. |
|
| 51:06 | then what happens? Then you right? If you hold your breath |
|
| 51:10 | enough, then yeah. All So we're just talking about normal breathing |
|
| 51:15 | and out. Now we can calculate out. So you can uh I |
|
| 51:20 | know if this actually it does have partial pressures, right? So you're |
|
| 51:24 | from 1 59 to 1 49. I'm not asking, please, |
|
| 51:28 | please do not memorize numbers, but going to show you two numbers here |
|
| 51:31 | it makes our lives easier to work these when you see numbers. So |
|
| 51:35 | you take into consideration air, moving and moving out and the oxygen always |
|
| 51:39 | down its gradient and so on and forth, what you'll see is that |
|
| 51:42 | average partial pressure of oxygen inside the is around 100 millimeters of mercury. |
|
| 51:47 | really like 100 and two. But know, put two in the penny |
|
| 51:54 | for somebody else later. Right. regard to carbon dioxide, it's roughly |
|
| 51:58 | millimeters of mercury. And those two are important because of what's going on |
|
| 52:04 | the tissues. We'll get to that a moment. All right, just |
|
| 52:09 | you there are factors that influence gas . These are again based on fixed |
|
| 52:14 | of one surface area is important. we talk about surface area, we're |
|
| 52:18 | if we want to have greater surface , we can open up the capillary |
|
| 52:23 | vasodilation. When I cause vasodilation, moves through faster, right? Excuse |
|
| 52:30 | , it's not the speed but the that's moving quicker through, right? |
|
| 52:36 | so what you do is you'd have exchange and so that's gonna increase the |
|
| 52:40 | of exchange. And the other thing can do is you increase alveolar |
|
| 52:45 | How do you increase alveolar space? my tidal volume? Tidal volume is |
|
| 52:49 | special word. That means how much I'm breathing in and out per time |
|
| 52:53 | breath. So this would be versus , low tidal volume versus a big |
|
| 53:02 | thickness that matters. We mentioned this . If I have water in the |
|
| 53:06 | , it's gonna increase the thickness of barrier. And then the weird one |
|
| 53:09 | the diffusion coefficient. Um You guys been in the chemistry lab before, |
|
| 53:14 | ? Have you looked around and noticed in the chem lab, they have |
|
| 53:16 | big thick books like this about this sitting over in the corner gathering dust |
|
| 53:21 | the CRC. Have you ever seen ? OK. The CRC is like |
|
| 53:26 | chemical reference something or another. And basically has every characteristic of every molecule |
|
| 53:31 | anyone has ever worked with, It talks like molecular weight, boiling |
|
| 53:36 | , melting, point, freezing Well, if there is a fact |
|
| 53:40 | one of these things, that's one will be found in the CRC and |
|
| 53:43 | can look up any chemical almost to that stuff out. One of the |
|
| 53:47 | that each molecule has is something that's a diffusion coefficient. And a diffusion |
|
| 53:52 | simply is its ability to uh solubilized a fluid. All right. And |
|
| 53:59 | if you look at carbon dioxide and , for example, you would see |
|
| 54:04 | the diffusion coefficient for carbon dioxide is greater than oxygen like 20 fold |
|
| 54:10 | All right. So what that means if you were to put oxygen, |
|
| 54:13 | dioxide on a slope, racing towards destination, the slope for carbon dioxide |
|
| 54:18 | be steep, the slope for oxygen be very, very slow. So |
|
| 54:22 | dioxide moves very quickly into uh uh environments like tissues. All right. |
|
| 54:30 | , why does this matter? remember we're exchanging oxygen for carbon |
|
| 54:36 | but carbon dioxide moves faster. So do we accomplish this? Well, |
|
| 54:41 | based on those partial pressures because there's much more oxygen there, there's carbon |
|
| 54:47 | again, we can go back and at the numbers if you want to |
|
| 54:49 | look at numbers, but there's so that they're offset. So the significant |
|
| 54:56 | millimeters of mercury of oxygen is off offsets that 40 millimeters of carbon |
|
| 55:02 | And so the exchange is roughly Despite the fact, carbon dioxide is |
|
| 55:08 | lot faster. All right. So doing some basic exchange here. I |
|
| 55:15 | think I need to explain this pressure . This is just a reminder you |
|
| 55:18 | know that. Right? Third you should know our friend Boyle shows |
|
| 55:25 | ugly face again. P one V equals P two V two. And |
|
| 55:29 | just shows you look at a constant pressure of a gas decreases if the |
|
| 55:33 | increases. All right. And that's here with this piston model, |
|
| 55:39 | You can see here when I pull the piston that decreases the base of |
|
| 55:43 | volume in or the volume increases. the pressure inside there decreases, |
|
| 55:48 | And if I press that piston the pressure is going to increase as |
|
| 55:51 | volume decreases. And all of these are important in understanding, breathing in |
|
| 56:00 | out. Do you guys like the ? I think the memes are much |
|
| 56:09 | fun in a class than just a . All right. So what is |
|
| 56:14 | ? It's moving the air between the and the elbow. Oli inspiration or |
|
| 56:19 | is drawing air into the lungs. or exhalation is pushing the air |
|
| 56:23 | OK. We're done. You can home. Well, there's more to |
|
| 56:28 | obviously, but that, I that's in essence, what we're gonna |
|
| 56:31 | is we're going to describe in minute how I make that happen. All |
|
| 56:36 | . That's in essence what this Quiet, breathing is what you're doing |
|
| 56:40 | now. Just breathing in and You're at rest. Some of you |
|
| 56:44 | at more rest than others. All . And so you're just that breathing |
|
| 56:49 | and out there is also called forced , forced breathing is when you actively |
|
| 56:55 | air or pull air into the lung would be forced, right? Same |
|
| 57:04 | processes are involved. Um So there's be autonomic nuclei that are stimulating the |
|
| 57:10 | muscles. So notice we can have pattern of regulation that is autonomic of |
|
| 57:18 | muscles so that we can create this of quiet breathing, but we can |
|
| 57:23 | that autonomic pattern as well. You hold your breath, right. You |
|
| 57:27 | breathe harder and faster, but it's at an auto autonomic level. And |
|
| 57:34 | we're doing is we're gonna be changing volume of the thoracic cage. And |
|
| 57:39 | doing so, we're gonna change pressure when we change pressure, air flows |
|
| 57:42 | to reach equilibrium, right? Or flows out to reach equilibrium. Where |
|
| 57:49 | we reaching equilibrium with the atmosphere? . That's the idea. All |
|
| 57:54 | And we're just moving air down its gradient. That's the whole purpose. |
|
| 58:01 | . This is the part where everyone getting confused. All right. And |
|
| 58:05 | , it's not confusing because of anything . It's because of how we look |
|
| 58:09 | it. All right, because usually taught in such a way that it |
|
| 58:14 | mucked up. So if I start you say you're mucking it up, |
|
| 58:18 | up, explain it. Right. . Um You hold me accountable |
|
| 58:24 | All right. Three pressures. We to concern her with self, with |
|
| 58:30 | pressure. That's the pressure of the . That's easy. We're just gonna |
|
| 58:36 | it nice and simple. Same thing learned since the dawn of time, |
|
| 58:38 | 60 millimeters of mercury. OK. gonna look at the pressure inside the |
|
| 58:43 | . All right. That is the pressure. So, inside the lung |
|
| 58:49 | , all right. Now it's gonna and fall. It's gonna go up |
|
| 58:52 | it's gonna go down. But what trying to do is it's always, |
|
| 58:55 | trying to reach equilibrium with the atmospheric . OK. So we're trying to |
|
| 59:03 | it's trying to get to 760 millimeters mercury. So far, pretty |
|
| 59:08 | Here's the thing that screws everybody up the intra plural pressure. So this |
|
| 59:13 | the pressure inside that plural sac. right. Remember one wall adhered to |
|
| 59:19 | thoracic cage. One part adhered to outside of the lung in there is |
|
| 59:24 | fluid that prevents friction. And what have is we have a pressure in |
|
| 59:28 | that's less than atmospheric pressure. So what's it trying to do? |
|
| 59:35 | would, what would something less than to accomplish if I have, it |
|
| 59:41 | try to, it would try to equilibrium, wouldn't it? So we |
|
| 59:43 | a pressure that wants to reach equilibrium is not being allowed to. All |
|
| 59:49 | . So let's kind of create the here. All right, we have |
|
| 59:55 | lung that is stretched inside the thoracic during development. You can think about |
|
| 60:01 | . The lungs are growing downward so they're not trying to fill the |
|
| 60:05 | , they're trying to just grow. because they're adhered to that uh serous |
|
| 60:10 | , they're being forced to stretch out spread in that little space that they're |
|
| 60:15 | their plural sac, right? But peal sac is also adhered to the |
|
| 60:20 | cage. The thoracic cage wants to outward. So we have two things |
|
| 60:23 | are trying to grow in different One's trying to grow that way. |
|
| 60:26 | trying to grow that way and they're that serous membrane. OK? I'm |
|
| 60:36 | because I'm trying to decide whether or I wanna do the demonstration here. |
|
| 60:40 | we wanna do the demonstration? What you think? You wanna do the |
|
| 60:46 | ? Anyone else, anyone else want demonstration? OK. They do. |
|
| 60:51 | like, I don't know. And know, you, you do, |
|
| 60:53 | want the demonstration? Excellent. we got three volunteers. All |
|
| 60:57 | I love it. Yeah. See, you knew it. He |
|
| 60:59 | looking at me like, please please don't come on up. All |
|
| 61:03 | , I want you, Sydney. . All right. This is what |
|
| 61:10 | it make sense? All right, have a stage. So this is |
|
| 61:16 | Shakespeare. Except far more interesting. right. What we have here is |
|
| 61:24 | have our plural sac. He looks like a plural sack. Don't you |
|
| 61:29 | he is fluid? So that's, is the cerus fluid over here. |
|
| 61:34 | have a cerus membrane over here. have a cerus membrane. What do |
|
| 61:38 | want to be a lung or thoracic ? All right. Come on up |
|
| 61:43 | is our thoracic cage. Now, thoracic cage remember is developing way over |
|
| 61:48 | and our lung is developing way over . All right. See, here's |
|
| 61:52 | lung. See our lung is way here, but they're connected to the |
|
| 61:59 | sac, aren't they? Uh oh , maybe a little bit. Got |
|
| 62:06 | whole answer. Comfy and everything. No, no. Get comfy. |
|
| 62:16 | it out. I want you to his arms off, pull his arm |
|
| 62:19 | . All right. Now, look we have here is we have a |
|
| 62:23 | sack that's being stretched, stretch All right. So you can |
|
| 62:29 | Let's, let's stop stretching for a . So if we don't stretch |
|
| 62:32 | what happens? He goes into equilibrium the atmosphere 7 60 millimeters of |
|
| 62:36 | But where do our, where does thoracic cage wanna be, wants to |
|
| 62:41 | over there. And where does our wanna be? So what happens |
|
| 62:45 | is now we're pulling and we're stretching that there's negative pressure inside the plural |
|
| 62:53 | . OK. Now, the reason that is we don't want any |
|
| 62:57 | Right? So if I pull on third, if I pull, what's |
|
| 63:02 | happen is he, he has to . There is no give. So |
|
| 63:05 | what happens. Let's move a step . All right. Move a step |
|
| 63:09 | . All right. Now, do see that? There's, there's give |
|
| 63:11 | . So now start moving away. how long it takes before there's |
|
| 63:17 | right? Do you see the So, the idea here is we've |
|
| 63:20 | stretched the pleura as far as we . And so the inside of that |
|
| 63:25 | is filled with a negative pressure and can't stretch any further. So that |
|
| 63:29 | any sort of movement in this relationship thoracic cage, pleura and lung is |
|
| 63:36 | cause movement of the whole system, ? So when the thoracic cage |
|
| 63:42 | it pulls the lung over and then the thoracic cage relaxes, the lung |
|
| 63:47 | back over to where she wants and arm stays stretched out. All |
|
| 63:53 | Does you see there's no give. what I'm trying to shoot. Thank |
|
| 63:57 | so much guys. Yeah. yay. Yeah, for volunteering. |
|
| 64:01 | get an automatic a for the Just kidding. Just kidding. All |
|
| 64:08 | . But that's what I want you visualize here. OK? So when |
|
| 64:11 | see that negative pressure don't become, my goodness. I don't understand. |
|
| 64:15 | we're doing is we're creating an environment that everything is already stretched out so |
|
| 64:19 | you have to get the interaction That any sort of change is gonna |
|
| 64:24 | transferred between thoracic cage and lung and and thoracic cage. Alright. See |
|
| 64:32 | thing is, is that fluid has cohesiveness to it. Do you guys |
|
| 64:38 | this from way back when and One and chemistry one. What is |
|
| 64:45 | ? Basically things sticking together, Water has with it. Polar |
|
| 64:50 | polar bonds are basically sticky bonds that the water from escaping. Anyone here |
|
| 64:55 | ever worked in a lab or had take two pieces of glass that have |
|
| 64:58 | to hear themselves together. I see shaking of the head. You must |
|
| 65:01 | had to do this before. you're working with plates in the |
|
| 65:05 | Those two things stick together. You as well use super glue, |
|
| 65:09 | You have to slide them until you not enough surface area and then the |
|
| 65:12 | things come apart. You want to this at home, don't use glass |
|
| 65:17 | reasons go get a Ziploc bag, a little bit of water in |
|
| 65:22 | push all the air out and then it and then try to pull the |
|
| 65:25 | sides apart. It's a nightmare because water serves as a glue and that's |
|
| 65:32 | going on in here. Is that can't stretch the water any further. |
|
| 65:37 | when you go through inspiration, what doing is you're pulling on with the |
|
| 65:42 | cage, you're pulling on the, the uh parietal side, you can't |
|
| 65:47 | the fluid. So the visceral side and so the lung moves and what |
|
| 65:53 | gonna do is you're gonna expand the cage outward and you're gonna push the |
|
| 65:58 | cage downward because of the muscles that involved. And in doing so that |
|
| 66:03 | the pressure inside the lungs. And the pressure drops inside the lungs, |
|
| 66:08 | wants to go and fill that. air gets pulled in from the atmosphere |
|
| 66:13 | fills the lung up until the pressure the lung equals 7 60 atmospheric |
|
| 66:20 | Ok. My muscle relaxes right. The thoracic cage falls inward, |
|
| 66:28 | The diaphragm moves upward, the volume the thoracic cage decreases. So the |
|
| 66:34 | rises inside the lungs. So what ? Air pushes out to win equilibrium |
|
| 66:42 | the atmosphere? 7 60 millimeters of . All right. The only reason |
|
| 66:47 | concern ourselves with that intra plural pressure to ensure that we understand that we're |
|
| 66:53 | stressing the system. What happens if poke a hole in the parietal |
|
| 66:59 | What happens? The lung collapses on because it's elastic tissue. It just |
|
| 67:04 | to become a little tiny deflated This is why it's being held and |
|
| 67:09 | I pulled them up here to show being stretched outward because the whole system |
|
| 67:14 | , is already, everything is out position. The lung is out of |
|
| 67:19 | because it's being pulled where it doesn't to go. The thoracic cage is |
|
| 67:22 | of position. It doesn't want to where it is and the pleura is |
|
| 67:25 | of position because it's being stretched as as it can be stretched. So |
|
| 67:29 | movement occurs because everything is already stretched so everything has to move together. |
|
| 67:37 | , there are muscles involved. You know these muscles. There's not a |
|
| 67:41 | list. That's good news. So breathing, the muscles are quiet |
|
| 67:44 | That's the diaphragm. That's the muscle separates the abdomen from the thoracic |
|
| 67:48 | If you're a singer, you know that is. If you're not a |
|
| 67:52 | , that's ok. All right, serves as the floor. So when |
|
| 67:56 | contract that muscle, it pushes the downward. When I relax the |
|
| 68:00 | the floor comes back up. The one is the external intercostal muscles. |
|
| 68:07 | means outside intercostal between the ribs. right. Your homework tonight. Go |
|
| 68:14 | a barbecue place, order ribs. you don't like pork, find a |
|
| 68:17 | that does beef rib, you'll be surprised. It's far better. Take |
|
| 68:22 | rib, take a bite and look you'll see, you're gonna see muscle |
|
| 68:27 | in one direction on the outside, the outer curve portion. That would |
|
| 68:31 | the external intercostal. What do you is on the other side? An |
|
| 68:36 | intercostal muscle. We'll get to that just a second. All right. |
|
| 68:38 | these are the muscles of quiet All right. When I contract |
|
| 68:44 | my thoracic cage expands, my floor . When I relax them, then |
|
| 68:51 | get those muscles to fall or the cage to fall in and the diaphragm |
|
| 68:56 | back up. Notice, quiet breathing both the inspiration and the expiration. |
|
| 69:02 | these two muscles are involved both in expanding and when I relax the |
|
| 69:09 | the contraction of the thoracic cage or loss of volume, that's what all |
|
| 69:15 | stuff is. Oh No, Exploration is just hard. If I |
|
| 69:19 | it, this is the greater detail it and this just shows you how |
|
| 69:24 | changing volume. All right. So is showing you inspiration and expiration. |
|
| 69:29 | vertical is the diaphragm lateral thoracic cage then also anterior and posterior would be |
|
| 69:36 | cage. All that's covered through the and the external intercostal muscles, quiet |
|
| 69:44 | , forced breathing. Remember what forced is? Watch me do forced |
|
| 69:49 | Watch carefully when I force breathe house different than my normal breathing. What |
|
| 69:57 | I do? Oh I lifted, lifted up my shoulders. So there's |
|
| 70:01 | muscles now that are being involved All right, let's do forced |
|
| 70:04 | I'm gonna exaggerate it, right. what did you see me do pushed |
|
| 70:13 | ? Right? OK. So here is an active process, unlike forced |
|
| 70:19 | like actual exploration. I'm not just the muscle to relax. I'm actually |
|
| 70:26 | involving muscles in exploration to increase the at which air moves out of my |
|
| 70:32 | . Ok. So both the exploration, I'm going to bring in |
|
| 70:36 | muscles. So in terms of I'm going to ask you to learn |
|
| 70:41 | of these, of this list of up here. All right. The |
|
| 70:46 | that I want you to know are shouldered ones. OK? Sternocleidomastoid and |
|
| 70:53 | Scalings. All right. They're the that make you do this. |
|
| 70:57 | It's the lifting up portion. And you're doing is you are trying to |
|
| 71:02 | the thoracic cage faster. All Now, these others play a role |
|
| 71:06 | that as well. I mean, the serratus, these are all muscles |
|
| 71:10 | play a role in pulling out but this is an anatomy class. |
|
| 71:14 | I don't want you to memorize So I figured the two s's are |
|
| 71:18 | easiest sternocleidomastoid and Scalings. And they a role in lifting or at the |
|
| 71:24 | . When it comes to exploration, bringing in two muscles. All |
|
| 71:28 | if the external play a role in inspiration, right? By lifting up |
|
| 71:35 | internal intercostal muscles play a role in inspiration by pulling inward, right? |
|
| 71:43 | the external are involved in both the and the regular inspiration, quiet breathing |
|
| 71:49 | well as forced inspiration. When I , I'm pulling, that's the internal |
|
| 71:56 | muscle muscle. So again, take rib after you've taken a bite, |
|
| 72:00 | see the muscles on the outer side this direction. You'll see the muscles |
|
| 72:03 | the inner side going the other Again, if pork's not your |
|
| 72:09 | I grew up in West Texas, didn't eat pork rib, we ate |
|
| 72:13 | rib. You know, it's like ribs. Good stuff. Lots more |
|
| 72:19 | too. Taste better. All So that's for express. No. |
|
| 72:24 | then the other one is the abdominal . That was the other thing. |
|
| 72:27 | just, we're not gonna list all abdominal muscles, but just say abdominal |
|
| 72:31 | are squeezing in. And what they're is they're pushing the diaphragm faster. |
|
| 72:34 | why li air is quicker. All , we're starting to wrap things up |
|
| 72:42 | . You're taking the physiology lab. . OK. One of the thing |
|
| 72:46 | guys get to do in the physiology is you get to play with |
|
| 72:49 | the spirometer. Um And the spirometer uh something that allows you to measure |
|
| 72:54 | lung volumes and capacities. And these just means by deter to determine whether |
|
| 72:59 | not your lung is working correctly. right. And so these are just |
|
| 73:02 | calculations that physiologists use. All So use a spirometer. This is |
|
| 73:08 | old fashioned spirometer. This is called Bell Spirometer. And so you breathe |
|
| 73:12 | and it lifts up the bell if ever seen the movie, um uh |
|
| 73:16 | the right thing or the right They actually showed the first astronauts using |
|
| 73:20 | spirometers and what that was one of first thing they're trying to test to |
|
| 73:24 | what's your lung capacity. And these were like being able to push air |
|
| 73:28 | like three minutes. It's crazy. What they do now is it's just |
|
| 73:33 | machine. You've done that, You go and you blow into a |
|
| 73:36 | . Not, not the one that's drunk driving. I'm talking a different |
|
| 73:40 | , right? Um So it basically the amount of air that's moved in |
|
| 73:44 | the condition of your respiratory status. and it can help you determine the |
|
| 73:48 | . All right. So let's just of go through them. All |
|
| 73:50 | So during quiet respiration, you need understand your lung is never completely |
|
| 73:55 | You're not a balloon, right? it never completely is empties, |
|
| 73:58 | So you're not squeezing all the air and squeezing in, you're not a |
|
| 74:02 | , right? You, you are bellow in the sense that air is |
|
| 74:05 | in and out, but you're not to the complete states of, of |
|
| 74:08 | extremes. All right. So this the lung capacity is about six liters |
|
| 74:13 | men, roughly 4500 for women. , that's a size thing. |
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| 74:17 | you know, on average, you , that's what you work out. |
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| 74:22 | Whether you're male or female, the breathing capacity is somewhere between 2700 and |
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| 74:28 | mils. So you're moving roughly 500 of air per breath. Right. |
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| 74:33 | , your lungs are never fully They're never fully, uh, |
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| 74:36 | full. They sit between 2700 and during quiet breathing. All right, |
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| 74:43 | can push out a whole bunch of and when you push out all that |
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| 74:47 | , uh, you'll be left with 1200 mils of air inside the |
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| 74:50 | Now, this is important. All . Um First you want to make |
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| 74:54 | that gas exchange is always taking And so if you push all the |
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| 74:57 | out of your lungs is gas exchange place. No. So that's part |
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| 75:01 | the reason, the way that we this is that when we push on |
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| 75:04 | lungs, what happens is, is collapse um those uh bronchioles like the |
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| 75:09 | bronchioles and the uh the respiratory And so it traps the air inside |
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| 75:14 | alveoli. So everything in the conducting is, it's not becoming empty, |
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| 75:19 | you're basically trapping air inside, but collapsing it. That's how it's |
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| 75:24 | So, our respiratory volumes, first is the tidal volume. That's just |
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| 75:29 | volume of air entering in and entering . So that's that little wave that |
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| 75:33 | see here, right? This little zone, right? The in inspiratory |
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| 75:38 | volume is how much air you can into your lungs on top of the |
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| 75:42 | volume. So, just think of breathing and when you breathe in, |
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| 75:46 | how much you can breathe on top that? All right, the extra |
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| 75:50 | reserve volume is the amount of air you can maximally remove from your body |
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| 75:54 | normal breathing. So that would be the down expiration. So I'm expiring |
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| 75:58 | then how much more can I push ? And then what's left over is |
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| 76:01 | is referred to as the residual So that would be that roughly that |
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| 76:05 | mils that is left over in the and then we can use these volumes |
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| 76:09 | we can do some calculations with So the Inspire or inspirational capacity is |
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| 76:14 | title volume plus the Inspire Reserve. it's basically everything blown up. The |
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| 76:19 | residual capacity, that is everything below title volume. So extra reserve and |
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| 76:25 | uh residual volume, the vital capacity everything above residual volume. And then |
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| 76:30 | total incapacity is all of four of together. All right. And |
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| 76:36 | when you go to a lung, life, when you went, if |
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| 76:39 | , when you have asthma, you have to tell me. But if |
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| 76:41 | did, I mean the first thing they do is they test your ability |
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| 76:45 | breathe in and out and they're, breathing in its barometer. So what |
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| 76:48 | looking for is based on your size your age and your sex and all |
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| 76:51 | fun stuff. They figure out what supposed to be. And then if |
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| 76:54 | doing less or more then they start to figure out what the cause is |
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| 76:59 | on these capacities. So these are . So this is an actual machine |
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| 77:04 | breathe in. Now it's not a barometer. So you have forced expiratory |
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| 77:08 | . This would be the percentage of capacity that you can expel in a |
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| 77:13 | of time. Usually it's a So it'd be like, ok, |
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| 77:17 | , how fast can you breathe out air? That would be that. |
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| 77:20 | then the Maxim toy Vol Voluntary ventilation , how much air can you inhale |
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| 77:25 | then exhale over that period of that . And these are just examples of |
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| 77:29 | . I'm not gonna ask you what two are and if I do then |
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| 77:32 | on me, ok, gonna pause for a second and then we're gonna |
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| 77:40 | to these things. Any questions so . All right, what I want |
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| 77:44 | to do is just know those definitions reasons, I guess because I had |
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| 77:48 | memorize them. So you, how's ? All right. Last little bit |
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| 77:53 | to do with the lungs ability to or to stretch. So compliance is |
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| 77:59 | much effort does it require to stretch distend the lung? All right. |
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| 78:02 | the last is how does it rebound ? Um, a terrible example of |
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| 78:06 | is if you go into the back your sock drawer, you might find |
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| 78:09 | sock that's probably older than five years you go grab that sock and you |
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| 78:13 | your hand in it, you'll feel pla the, the elastic fibers kind |
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| 78:17 | a broken down. And so they'll just fine, but it won't, |
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| 78:22 | won't go back to its original So, what you'd say is it |
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| 78:25 | failed elastin, right? The compliance would be, oh, you go |
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| 78:29 | that sock drawer and you try to your hand into a sock and it |
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| 78:32 | to stretch on you. All That's, that's what it is. |
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| 78:36 | this is your lung responsiveness. And this is gonna be based on a |
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| 78:40 | of different things, how much Elastin present. So, if you've destroyed |
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| 78:43 | Elastin through smoking, it becomes much harder to breathe. Not because there's |
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| 78:49 | Elastin is because you baked it And so you can't stretch your |
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| 78:52 | And so it takes more work to your lung and then it takes more |
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| 78:55 | to push it all back in. why you see people with uh COPD |
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| 79:01 | because they're working to get the air and out of their bodies. They |
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| 79:05 | to be the physical bellows as opposed allowing the muscles to naturally go back |
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| 79:09 | place. The other one is surface . Surface tension has to do with |
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| 79:14 | attractiveness of water mole molecules to other molecules. All right. So what's |
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| 79:21 | happen is, is if you just water in the lungs, so think |
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| 79:24 | the humidity just in the air you in, that air water goes into |
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| 79:28 | lungs. If there's no surfactant, happens is, is the water molecule |
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| 79:31 | attracted to each other and they carry them. The other things that they're |
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| 79:35 | to, the other thing that they're to is the surface of the |
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| 79:39 | So the surface of the alveoli. when water goes in there, it |
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| 79:42 | causes the alveoli to collapse. Have ever have ever had to blow up |
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| 79:47 | balloon for a party? Right? you're blowing, blowing, blowing, |
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| 79:51 | accidentally let all the air out. like, damn it. Right. |
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| 79:54 | if it didn't have cornstarch in what do you now have is a |
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| 79:57 | that refuses to blow up at all all that air that you pushed in |
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| 80:01 | with all that wet spit is now on the inside and it's like, |
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| 80:04 | , look at me, I'm super . So what do you do? |
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| 80:06 | just throw that balloon away and you all over again? You ever do |
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| 80:11 | ? Ok? You need to get more. Go to a kid's |
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| 80:16 | start blowing up balloons, right? can do your own party too. |
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| 80:20 | ok. It doesn't have to be kid's party. But if you feel |
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| 80:23 | blowing up balloons, there you All right. So the purpose of |
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| 80:27 | surfactant is to counter the effect of polar bonds. In essence, what |
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| 80:32 | is, is a bunch of lipids proteins. That are uh are inserted |
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| 80:37 | between the water molecules. And when insert into the water molecules, what |
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| 80:42 | up happening is, is the water no longer interact. And if the |
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| 80:45 | can no longer interact, it no pulls the sides of the alveoli |
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| 80:49 | So when you deflate, what happens you don't deflate and pancake out and |
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| 80:54 | . Instead, you just kind of a little bit and you maintain that |
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| 80:59 | structure. All right, when you that rounded structure, it's a lot |
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| 81:03 | to expand. So again, think a balloon. If the balloon has |
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| 81:07 | air in it, is it easier inflate? Yeah, apart from the |
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| 81:13 | , once it's stretched out a little , it keeps going. So notice |
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| 81:16 | when you do that balloon, what you do? You hold it like |
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| 81:17 | and you're like, and you get first and you trapped there and then |
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| 81:22 | like it doesn't take much more And that's what's going on inside the |
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| 81:27 | . That's what the surfactant allow. maintains the partial shape so that you |
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| 81:34 | reach equilibrium. The last little thing it does is that it affects um |
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| 81:39 | how air moves between the LVO See, there's a rule, it's |
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| 81:42 | the law of Laplace. I I don't know if I have it |
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| 81:45 | the other slide. I don't. Yes, I do. It's |
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| 81:47 | there is the equation right there. what it says is, there is |
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| 81:50 | relationship between tension and rating and that's relationship again, you know, I'm |
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| 81:55 | gonna, I'm not gonna ask you memorize the formula here, but basically |
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| 81:59 | says the smaller the radius, the the, the inward pressure, |
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| 82:03 | And so you can imagine if I two alveoli of, of equal size |
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| 82:07 | of different sizes, the one that's is gonna drive air out of it |
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| 82:11 | the larger one. Ok. And if I want to get air |
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| 82:15 | that's gonna reduce surface area and if reduces surface area, that's bad. |
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| 82:21 | , surf, what surfactant does? allows the air to equilibrate between the |
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| 82:25 | different sizes. It modifies the tension those smaller vessels so that the tension |
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| 82:31 | equal between the two spaces you preserve area. I caught us up. |
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| 82:38 | means the last lecture is going to easy. All right guys, I |
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| 82:43 | see you on Thursday. Let's let next class in as quickly as |
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| 82:47 | If you have questions, email me come and see |
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