and here we go okay so it is monday uh today's february uh february my goodness i don't know what made me say that um november 15th and uh we will uh continue on our lecture on respiration and so let's take a look at the powerpoint we were left with last time let's see if i can find it on the share screen and there it is hopefully it pops up nice and neat okay so there is the close-up of the end of the tube now i'm gonna backtrack a little bit for those of you if you remember you know when we talked about um the bronchial tree or the or the branches we said that you know we have a trachea a single windpipe and listen to this in that a sort of like pairing a single windpipe for a single respiratory system then this little triangle of cartilage little bikini shaped cartilage here that helps the trachea split into two primary bronchi bronchus is singular so you have a right left primary bronchi two primary bronchi because they represent two lungs then we discovered that after that the primary bronchi split into secondary bronchi when it came to secondary bronchi we discovered that there's actually let's see if we see a picture of it here hopefully i don't have to go back too far here we go i don't know if this shows it very well no that does not show it very well okay well the secondary bronchi subdivide and uh the left lung is supposed to have two secondary bronchi but meanwhile the right lung has three secondary bronchi why the unparalleled nature of our secondary bronchi why is there three on the right and two on the left because there's three lobes on the right that's right see the secondary bronchi see two primary bronchi feed two lungs they're on the screen right now the secondary bronchi subdivide into the lobes of the lungs the lobes of the lungs are compartments of the lungs it's like walking into a building and one building has three floors you walk into the left wing of the build of this complex and the left building only has two floors all right although they appear to be the same size they're actually not the same size the right lung is slightly bigger and the main reason for that is because of the heart's positioning the heart position leans slightly to the left and because it leans slightly to the left it takes some of the volume away from the left lung and so the left lung has this very specific superficial characteristic known as the cardiac notch that you see right here in this little curve right in this area right here and if you're not seeing it i'll put a little box around it okay there is the the cardiac notch okay so three secondary bronchi feed the three lobes of the right lung two secondary bronchi going to the left supply the two lobes of the left law okay so when we look at our bronchial tree we start to realize each subdivision is going to a different partition of the lungs that the lungs are actually compartmentalized i don't know if i can say that very clearly it's in compartments so now after the secondary bronchi we go to the tertiary bronchi the tertiary bronchi actually feed the segments of the lungs so each lobe is actually further divided into segments okay on my analogy you go to the third floor of that three-lobed building and on the third floor there are several wings the 100 rooms are over here the 200 rooms over there the 300 rooms over there the 400 rooms are over there so you've got several segments segments or further divisions of the lungs and then when we finally get to your bronchioles the bronchioles are going to be feeding the lobules of the lungs and those are the smallest parts of the lungs the lobules that are filled with alveoli and alveolar sacs etc that we see at the very end here so this represents a lobule of the lung all right now just to give you a little side note the significance of that is the fact that if a person is detected to have a tumor on the lung if they catch the tumor through chest x-rays or whatever it may be if they check or or detect the tumor early enough they may actually be able to take that little segment of the lung out and cap it off and the rest of the lung will be normal so in other words if the tumor is small and they discover it in one of the segments of the superior lobe of the right lung they can literally operate and take and remove that particular segment of the lung and as long as there's no evidence that the cancer is spread they can feel fairly confident that they caught the cancer in time before it metastasized now let's say another patient goes in and they discover oh no the cancer is in one major lobe of the lung they can literally again remove that lobe of the lung because it's isolated and save the rest of the lung so the compartmentalization of the lung actually makes it great for early detection of cancer and that's why they always say the earlier you detect the cancer the easier it will be to treat and the lungs are a perfect example of this all right so because the lungs are subdivided you can actually remove a piece of the lung and leave the rest of the lung as long as the rest of the lung is healthy all right and that's what we saw before but let's get back to our alveoli so we finally bring air into the alveoli and we discovered that the deeper you go into this tracheal tube certain changes took place so let's summarize those changes okay let's see sorry i just have a question yeah um so it goes from the secondary bronchi which go to the different lobes then it goes to the tertiary bronchi which go to the different segments segments they're called bronchopulmonary segments let me show you where that word was i know it was here somewhere there it is bronchopulmonary segments so when i say segments of the lungs yes they're what the lobes are divided into that's the full name go ahead continue the tertiary bronchi feed the the segments of the lungs and then it goes from the tertiary to the alveoli from the tertiary watch look at the diagram that's on the screen now from the tertiary it goes into smaller bronchi which we just ignore the tertiary bronchi eventually become turn into bronchioles and these bronchioles and terminal bronchioles will feed the lobule of the lung so here you see the word lobule so the bronchioles will feed the lobule so that's the division if you want to go any further than that then at the very end of that you could say and the alveolar duct feeds the individual alveoli the air sacs okay so you have everything in size order you wanted to make sure you had that straight correct exactly thank you okay and that's what i was about to review right now in general though okay so when we talk about the bronchial i was in the middle of writing bronchial tree we basically know that as we go through the bronchial tree certain changes take place okay so obviously in terms of size okay the tubes get smaller okay they get smaller in diameter obviously all right as they get smaller in diameter certain other things begin to change as well okay do we end up getting more and more cartilage or less cartilage less less yeah there's less cartilage in fact it gets to a point where remember when you reach the bronchioles there's no cartilage okay and when you reach the bronchioles there's no cartilage instead the these tubes are supported by smooth muscle okay and that's what allows uh you know them to you know similar to blood vessels vasodilate or vasoconstrict but anyway uh let's continue with our tube so the tubes get smaller there's less and less cartilage and what happens to the cells that line them well if you remember they started off as pseudo stratified yeah and obviously when you're making a tube when the tube gets smaller after a while you can't support pseudostratified so you go to straight columnar then to cuboidal and eventually when the tubes get so small the only cell that will actually make a tube will be simple squamous now the unusual thing is every one of these is simple so obviously every one of these is very very delicate tissue so as you go through the tubes the cells change shape now if i didn't make it clear enough let me show you what i mean if you have a tube that's this big okay then you could probably afford to have a lining underneath that let me let me see if i can do this i don't know if it'll work but i'll try a little bit better than that let's see that's not so bad okay if you have a big enough tube you could see where there's plenty of room for columnar-like or pseudostratified columnar cells to fit in here so i'm drawing you like a model of let's say a primary bronchus okay here's the lining of it okay and of course there's cilia on the end here those are the cilia okay and if it's pseudostratified we have those base cells in here too that make it look like not all the cells reach the surface and then if i was drawing nuclei of course we'd have little nuclei in here sorry about the disruption of this the cells here but anyway okay so i'm putting a nuclei in there trying to put a nuclei in every cell back up there's two nuclei in there that no good this one there okay well you get the idea imagine the whole thing is this so this would be an example of oh i'm just making this up a tertiary or secondary bronchi that are big enough to have the uh the pseudostratified cells in them okay but then when we get further down the tube gets smaller and when the tube gets smaller you don't have the same diameter to be able to fit all these so in other words you might not be able to get the full extent of pseudostratified so you'll only have enough room for simple columnar okay a slight difference and again there's cilia in here going all the way around it and so on and so forth but if you see where i'm going when the tubes get too small we'll now columnar is not going to work instead we have shorter cells so these cells now are going to be more cuboidal all right and then if i add cilia well do you see what's starting to happen the inside of the tube that air is trying to go through it's starting to get congested a little bit so as tubes get even smaller now it gets to the point where you know what there's no way even a cuboidal cell is going to fit in there okay these cells better be flat and when these cells are flat obviously these tubes are made up of simple squamous cells so as you go deeper and deeper into your bronchial tree you start to see a histological change an adaptation for size big tubes can accommodate the pseudostratified cells with lots of cilia a little smaller well now we we we take in simple columnar cells also ciliated by time we get the simple cuboidal it's like these little cells in here the cilia are starting to get in the way and then eventually when we get to flat cells there's no room for cilia at all and these are the cells that are one cell thick and that would be examples like what we see here okay the cells that we see here would be like the alveolar duct uh the respiratory bronchioles that we see over here okay and even some of the cells up here this tiny little bronchial we see here doesn't look very thick might be made out of cuboidal cells that's my guess okay based on the fact that the nuclei and it's fairly thick here that you see it in this area right here i don't know if you you could see where i'm pointing at but in this area right here um you can see that you you see nuclei going around in a circle and i would guess if i put little divisions in there you might make out that yeah they look like cuboidal cells they don't look totally flat yet but they definitely are not columnar cells okay so this histology definitely changes and based on what i just said you can see that there were some other changes as well what happened to the amount of cilia that these tubes can accommodate yeah it decreases it decreases to the point where in some of these tubes of the columnar tubes leading into a cuboidal um lined tubes that there's actually no room for the silly the cilia get in the way and obviously these cells here could have no cilia at all uh and we also indicated what we didn't indicate but we sort of suggested by our definitions when we look at cartilage okay remember cartilage supports these tubes so in in your trachea remember okay in your trachea there are s wrong color in the trachea remember there are c-shaped cartilage that support this okay in your secondary and tertiary bronchi there are also c-shaped cartilages that support this in some places okay but eventually when you get to the tertiary bronchi remember the amount of cartilage decreases to the point where there is none so we'll do the same thing for amount of cartilage amount of cartilage oh we said it already i'm sorry less cartilage is up here okay sorry i'm repeating i i thought i had said it before okay and of course the thickness of the tube is getting thinner and thinner all right so we went through it all right we went through all the changes that take place okay any questions on the tubes what they're made up of or what they're bringing air to professor i had a quick question okay i was wondering if if you could just like repeat when you said about the the um what is this i don't know if i can pronounce it right square means the squamous cells yeah the squamous cells the squamous cells are the cells that are totally flat you know when you look at them under the microscope they look like little sunny side eggs with a nucleus in the middle but when you look at them side view they look like this they're very very flat cells so what i said was when the tubes are holding columnar cells like you see here when the tubes get smaller then it's almost like columnar cells won't work so you have cuboidal cells when the tubes get even smaller what you do is the cell the the wrappings of the cell are only made out of these flat cells so you take one flat cell and you wrap it like that and then you take another flat cell and you wrap it like that you have another flat cell so the tube is actually made out of flat cells and these would be things like i said your respiratory bronchioles the alveolar ducts they're only made out of one single cell and that's the simple squamous cells that are making them up i think that's what i said and of course they're so flat they can't have cartilage well they don't have cartilage they don't have any supporting cartilage on the outside they don't have any cilia okay uh and uh basically they're just little tiny little tubes supported maybe by a little bit of smooth muscle okay that might be like like some smooth muscle cells out here at most so they're not supported by cartilage okay they might be supported by smooth muscle like you see here here's some smooth muscle cells going around the respiratory bronchioles that you see right here or the term the terminal bronchials all right any other questions okay so let's clear this and get into the specifics now that we've brought air all the way into here what happens next well when we go into those tubes okay if we looked at under the microscope now you're seeing what it looks like your lungs look like a gigantic sponge made up of a mass of these air sacs okay and these air sacs create a tremendous amount of surface area now i don't know the exact number but i remember somebody said if you took your lungs and you laid out all those alveoli cells those simple squamous cells are laid out flat it will be enough to cover an entire football field or two there's a lot of surface area in your lungs and you know what these the surface areas for okay you need all the surface area and all these air sacs that you see here in the micrograph because you're going to be absorbing oxygen you want to get oxygen in here oxygen is going to be absorbed through these little walls now you might be wondering absorbing these little walls to go where what you don't see in this diagram here is right in here are your capillaries your capillaries are actually going around every one of these tubes those tiny little skinny little one cell thick capillaries that you learned about in the in the last unit are embedded in here they create this gigantic capillary network so that way your capillaries you know the old hemoglobin that's in there and the red blood cells that are in there remember traveling in single file they're going to be picking up the oxygen meanwhile you know do the exchange the blood is going to be getting rid of carbon dioxide and that's going to be dumping the carbon dioxide in the tubes so let's see how this happens let's see how this actually does happen all right now i notice that these bigger openings here are called alveolar ducts all right because those are the tubes that are bringing air into all these little dots here so here you see uh in this diagram here which is further away lower magnification you can see the respiratory bronchial bringing in air the air goes to the alveolar duct here's where the air is going through and then you've got this gigantic sponge around here just ready to absorb the oxygen and get rid of the carbon dioxide okay then after you're done you're gonna exhale and so all this is gonna go out the same way so your lung is this gigantic sponge so let's look at the detail of one alveolus or one alveoli cluster so that way you can see how well you are equipped for the shot okay here again is a close-up and i want you to notice notice this cobweb nature okay these are the simple squamous cells that are making up your alveolar that's why it looks like it's mostly space and and here's a very very close up with a micrograph that's showing this okay so when we look up close and let's get to this part okay this is showing you the capillary beds okay so like we said around the alveolar sacs or these capillary beds that are there oh remember this and if it's blue it's a pulmonary artery bringing deoxygenated blood in and then it gets the oxygen dumps off the carbon dioxide and the red leaving is the pulmonary venule that is leaving so if somebody said to you take a look at this okay which way is the blood going okay would you be able to do this this is where the blood is coming in that is the pulmonary arteriole bringing the deoxygenated blood in and this is the pulmonary venule carrying the oxygenated blood out and where is this blood going over here who remembers that the aorta no not to the aorta to the right atrium not the right atrium think think think leaving the lungs no no we're now we're near the stomach area yet we're leaving the lungs focus for a minute we're leaving the lungs and we're heading back to where the heart again and which part of the heart ventricle well we can't go to a ventricle until we go to a what first right yeah and i keep hearing you saying right atrium okay wait stop don't don't say anymore okay i'm gonna try to draw a quick heart for you okay now that you're looking at it okay you want another hint okay now here's a close-up of the lung and here is the pulmonary vein that's going back to the heart back to what part of the heart the left atrium ah see that the left atrium is the one that receives the oxygenated blood all right when you were saying the right atrium i couldn't accept that because look the right atrium is the one that's filled with deoxygenated blood this is the side of the heart that received all that deoxygenated blood from the body remember the superior vena cava the inferior vena cava came in this was all deoxygenated and then it was the right ventricle that pumped this deoxygenated blood out through the pulmonary trunk and went to the lungs see so this is the pulmonary artery right here arterial on this side the blue side remember this opposite colors you remember that now but the red side okay the pulmonary vein that was carrying the blood back to the heart it had to go to the left atrium then you would have the thick left ventricle and i didn't draw it that way i'm sorry it was a freelance but uh the the left ventricle is the side that's gonna carry and pump that oxygenated blood to the whole body to the head to the arms and down here to all the other organs that were down there okay i figured i'd throw that out there i didn't realize it was going to be a five minute little review lesson but i think it's worth it everybody see it now yes okay everybody should understand it now better okay yes yeah because the oxygen is is the oxygenated side of the heart is the left side that's the pumping side that's bringing blood to the whole body okay all right now i feel better okay so let's get a little closer to this so when we look inside now it's time to take some serious notes okay the structure of the alveolus the structure of an air sac we know the air sac is designed to absorb oxygen and get rid of carbon dioxide and it has this gas exchange with the bloodstream so if you were able to look really really close into the air sacks of your lungs this is the detail that you would see so let's make a list structures that are in our alveoli what makes it functional okay number one on our list is exactly what we see here okay number one we see that the alveolar structure is made up of simple squamous epithelium okay those are the simple squamous cells that you see there in the picture and let me see if i can stretch this out just so you can see all the words i'm writing okay now of course they don't call these cells simple squamous epithelium okay and they call them let's see if my my words are in the way yeah they are a little bit away let's see if i can lower this and and it's not really that important but i'm going to lower this slightly so you can see it okay these are called pneumocyte type 1 cells that's what the book calls them notice i'm not even gonna write that down but if you want to you can okay these are the pneumocyte type one cells okay i personally i'm not a fan of new words for no purpose at all okay if you know your air sacs are made up of simple squamous epithelium that's what i want you to know notice they're one cell thick see right here one's so thick there's nucleus they're very very flat cells and they make up this whole air sac that's right there there's lots of them okay and these are the simple thin cells that allow the passage of oxygen so to no surprise we know that oxygen is going to go through these cells right here right into that capillary so these red arrows are representing how oxygen is going to get right through and notice the capillaries are also made up of a single layer of simple squamous cells so the thinnest membrane in your body is right here okay this is called your respiratory surface okay so it's made up of simple squamous cells okay and what we'll add to that is star star with your capillaries it makes up your respiratory membrane star star okay this makes up your respiratory membrane one of the thinnest membranes in your entire body that's from the outside world to the inside world and if you remember from your definition the gas exchange that's going to occur here okay whether it's oxygen going in or carbon dioxide leaving remember we call this external respiration okay this is external respiration that's happening here okay so if you want to add that as an additional note you can say star star this is where external and make sure you underline the word external respiration takes place okay so are you picturing that in your head where we're we're shrinking you you're inside your lungs right now and you're sitting inside your lung and you're looking at this and saying ah so this is where the oxygen gets into my blood that's called external respiration okay you look at your old definition it was the exchange of gases between the blood i'm sorry between your air sac and your blood okay it's the movement of air into your bloodstream from the outside air okay so i know a lot of students often get confused with why are we calling it external when it's happening in your lungs but remember it's an exchange between external air and your bloodstream let's spell the two o's okay that's why it's called external because it's going from external air into your blood questions i had a quick one so that that's our lungs yep this is if you took like a little camera okay and you went inside your mouth and you went all the way down down down down at the end of your lungs at the end of your air sacs this is what it would look like it's it's in a cartoon of course but this is what it would look like the whole inside of your lungs is made up of these simple squamous cells and on the outside of the simple squamous cells oily capillaries okay the capillaries that let's see if i can do this without messing things up the capillaries that you see here see right here okay so we went inside your lungs in these air sacs these little purple things and now we're looking at it up close okay no um i didn't see it i couldn't see i don't know man okay can you see this picture now yeah i can see the picture now okay when i switch drawing something but i didn't see it no just now what i was showing you is i i went back a picture do you see this picture now when i change yeah okay i was saying these purple things right here okay these little purple circles they're over here but it's underneath the print those are the air sac so what we're zooming in and is we're going inside that and when we go inside that this is what we see oh okay i got it all right yeah so we're inside here so i i if you just happen to be okay all right joseph i got your message hopefully everything will work out you'll stay with us if not we have the recording okay uh so if you were inside here okay so you know here you are standing right here okay you'd be standing in an air sack you'd be suspended around and you look around and you would see the wall and when you look at the wall the wall is made up of these simple squamous cells okay but what you don't see is on the other side of the wall are the capillaries the capillaries are inside the wall and i said here it makes up your respiratory membrane okay and that's where the exchange of gases take place now but then you look around and then you notice wait a minute i see a very unusual cell right here what is that cell looks like it's got little fingers sticking out wait wait a minute i see another one over here what are these special cells with the little fingers sticking out well that's number two number two these are called well they have a number of different names okay these are called sir factant cells okay or sometimes they're called uh let's just keep them as as surfactant uh surfactant cells they they have another name that is is also in the textbook not important right now what's more important is that the these these cells that are there uh these surfactant cells they produce a non-stick secretion to stop lung collapse okay they create surface tension okay and by creating surface tension they keep the air sacs opened okay um i i i'll write it down with a question mark next to it i believe they're also called septal cells i'll have to look that up okay you know what it is the new book cells are driving me crazy the new book uh terminology yeah these are the ones that they call pneumocyte 2 cells okay and again i will never use these words okay pneumocyte two cells pneumocyte one cells say nothing to me you know it's a name that somebody in albany made up to sell new books i purposely personally feel like the guys who make your your textbooks sit around every year or two and say okay we gotta make the 11th edition of the book we've got to make the 12th edition of the book so what are we going to do well we've got to change at least 20 new words so let's make up 20 words add them to the book change a few diagrams and sell a brand new book on anatomy and physiology that hasn't changed in quite a long number of years so it it i think it's just a publisher's way of of of of justifying selling a new book by changing the words okay but there's no purpose in changing the words so anyway that was my little advertisement all right so i'll get off the soapbox and get back to nara notes so what are the alveoli made up of they're made up of simple squamous cells that create the respiratory membrane so you're getting the key facts from me and this is where external respiration takes place okay there's also surfactant cells or these septal cells okay that create a non-stick surface they create a secretion that for the most part keeps the tubes open so when they secrete something the secretion goes all the way around here now it's not mucus it's something called a surfactant and it keeps the air sacs open okay so that way there's there's less static electricity that's going to keep it together um [Music] okay premature babies again a little side note about these cells premature babies normally don't have surfactant cells that have formed yet okay they're preemies so because they're born without these surfactant cells they have difficulty breathing that's why little preemies are usually put on respirators and the march of dimes they do a tremendous amount of research on um on premature births and birth defects and things like that and years ago they actually came up with a new invention they created a baby a preemie baby respirator that not only brought air into the baby's lungs but it also created a little spritz and they're actually able to add surfactant to the infant baby's lungs to keep their lungs operating and with that invention they've actually increased the percentage of infant babies actually surviving all right so the survival rate of preemies have increased quite a bit because of the importance of that surfactant and they figured out a way in which they could spritz in pump in a little bit of surfactant into the delicate baby's lungs to keep them breathing longer on the bad side of things i mean you you have uh you know you have diseases respiratory diseases where where the mucus of the lungs is so thick that it doesn't even allow the exchange of gases okay and uh and and and so you you have the opposing conditions where the thickness of the mucus blocks the the air passageway so these air passageways are very very very delicate and hopefully a few of you are thinking gee so what happens when i'm smoking and smoke is getting in here you know well thank goodness you have the third group of cells for the most part your third group of cells are really not part of the lungs okay these are called al o lr macrophages or phages okay they have a nickname also they're called dust cells okay and they're clean up cells these alveolar macrophages are very much like monocytes they wander around and you know like the custodian cleaning up the building after everybody is gone these alveolar macrophages are basically cleaning up the area so if dust went in there they'd be able to gobble up that piece of dust if a little bit of fiber or something from the air snuck into your lungs so these are dust cells these are cleanup cells that try to clean up as much much as possible but back to my question so what happens when you smoke well obviously you are bringing a tremendous amount of dust in here you're overworking your alveolar macrophages and a lot of mucus gets secreted and the mucus sort of piles up in here and so you end up having mucus piling up in here you have these alveolar macrophages that are overworked and you start developing smokers cough because you're trying to cough up and get rid of this mucus that's clogging up these delicate air sacs all right and then eventually if you keep smoking then you have something even more uh potentially deadly and that would be taurus and nicotine and what the tars and nicotine are going to do is they're going to coat the lining right here and when the tars coat the lining they're actually blocking your air sacs and now you have less of a chance of getting oxygen the tars block the area here and cover this entire area with tar so that way oxygen cannot get through and it makes it harder to breathe and so you develop a cough because you're trying to cough up all this excess phlegm you're trying to get rid of this and get it out of your lungs to clear it up but even if you do get rid of that phlegm by a cough you still have these tars that are sticky and they stick to the inside lining of your lungs and make it harder and harder to breathe now they do say that if you stop smoking eventually and nicotines will will dissolve away and eventually the the body will repair itself okay and so if that does happen that would be nice to see that your lungs are nice and clear and back to normal again okay any questions about the structure of your alveoli three basic cells that are in there trying to keep you breathing um this is just like a general question relating to the smoking part so would it be possible for let's say the negative to like or like any of the bad substance to enter the capillaries well well since you mentioned it okay so far what i was talking about was particles okay the particles from the smoke okay that that i i showed by uh by drawing this that's the particles of the smoke the tars that i drew i drew like this okay but when you talk about nicotine all right nicotine is a chemical okay nicotine definitely goes in the blood nicotine is what gives us that little buzz that little lightheaded feeling when we smoke yes so nicotine is actually a drug it's a habit-forming drug okay it's a little bit of a stimulant it increases your blood pressure increases your heart rate like i said it gives you a little light-headedness a little buzz and uh and and that's the part that's addicting in smoking so yeah that part of smoke goes into your bloodstream okay so just the chemical really not really like the substance itself of tar no no tar is is is the sticky part of of uh you know the the burning leaves you know tobacco is a leaf it's a plant product and so when you smoke it and you burn it the other there there's a little stickiness a little residue that uh that is left in there so tars are or clogging substances the dust in smoke is clogging but nicotine is something that goes into your bloodstream that affects you metabolically that actually creates the addiction oh okay then yeah that's why they sell like nicorette gum so don't smoke just chew nicorette gum and you'll still get that little bit of high i don't know if they even sell that stuff anymore all right but they used to they used to try to convince people you could stop smoking just chew nicorette gum you get that little buzz from the nicotine in the gum and uh and you resist the temptation to smoke uh but for some people smoking is a physical habit as well because you just feel i don't know whatever you know you know like teenagers want to feel grown up so they smoke just for that look you know uh you know seeing bob dylan hanging a cigarette out of his mouth back in the 60s made it a cool thing for rock musicians to smoke while they're playing their guitar or hang their cigarette on the strings of the guitar remember that in my generation so it was sort of like a you know a a status symbol i guess but anyway i'm totally off track right now okay so that's the difference between the nicotine effects on the body versus tars and dust okay let's clear this up i'm going to take a picture of this mess okay so we we spoke of the structure of the alveoli and now you have a little idea of external respiration okay here's a close-up of the membrane so remember we said what is your respiratory membrane made up of so if you didn't write it down before you could write it down now okay your respiratory membrane is made up of right there your alveoli epithelium okay the single cell okay i like the way they did this diagram because they're they're showing you the sub components of it as well okay so what's on the alveolar surface see that little light blue area right there there's a surfactant as a surfactant that keeps it from sticking okay then inside you have the wall of the capillary so there's the wall of the capillary also made up of simple squamous cells okay and just for size portions there's a red blood cell so that's how thin this membrane is they show you a number here whether that number means anything to you okay but a red blood cell was supposed to be seven micrometers across not that i expected you to remember that okay so red blood cell has a diameter of seven micrometers the thickness of this wall is only a half of a crack micrometer okay so so this is very very thin wall red blood cell is huge compared to that okay actually 14 times larger okay and and that's what you see here so again the reason for me to show you this is to show you how thin this wall is okay and how delicate it is because here is the air you breathe out here okay so out here is the air you breathe and whatever you breathe in your air okay it's going to get through this thin membrane and into your bloodstream okay so hopefully it's oxygen going in of course i want to make that symbolic i should make this all red hopefully it's oxygen going in and you know what i'm about to do and carbon dioxide leaving okay and again we call that external respiration the exchange of gases between the outside air and the bloodstream okay professor yes so um if we were asked uh like what are the components of the capillary we would say what alveolar epithelium surfactant fused basal lamina and endothelium be careful you just asked me and i typed it as you said it if i asked you what's the structure of the capillary yeah the capillary is made up of a single layer of simple squamous cells or endothelium and the theoleum is the name of the membrane and simple squamous cells are the names of the cells so that's let me let me put a box around it this is the part that's capillary this is the part that's alveoli now what you just described to me is the perfect answer for what is the structure of the respiratory membrane now say all those words in your head okay what is the structure of the respiratory membrane the structure of the mesh respiratory membrane consists of the endothelium of the capillary the alveoli epithelium of the alveolus and there is a little bit of basal lamina that acts like glue okay so i didn't mention that but that's that's this part here basal lamina is like cell glue it holds membranes together okay so it's not like two sheets of paper but it's two sheets of paper with a little bit of elmer's glue in between okay did i clear up your question yeah thank you okay so let's get on with this so we can get to the processes involved and so [Music] let's clear this and we start to see the gas exchange here's our gas exchange navigator so notice the words here pulmonary ventilation another name for breathing on this side we have external respiration okay so for and on this side we have gases being exchanged with your cells so this is internal respiration so the vocabulary will first stay is being shown to you right here so let's examine this a little closer we're not going to get into this this has to do with breathing volumes okay but let's do pulmonary ventilation real quick and see how much you remember if you actually watch the videos okay this is showing you the changes in pressure and what your body does when you're inhaling and exhaling so if we quickly summarized all this we would say pulmonary ventilation okay you would immediately say well we have to break that down into two parts okay well not what i wanted to do that's good enough click okay we found out from the videos they have inspiration is the fancy word for inhalation or inhaling okay so who remembers when you inhale what happens i'll give you a hint what happens when you inhale diaphragm expands expands i'm not quite sure what you mean by expanse expanse makes me think of a balloon going out here's the diaphragm look at the diaphragm down here okay what's the diaphragm gonna do when you inhale it's gonna move down it's gonna move down yeah it literally it's a dome-shaped muscle if you can see my fingers in my diagram on my face okay it's a dome-shaped muscle when it's relaxed so it actually contracts and when it contracts it actually straightens out and goes down so what i'd like to add to our description and again you can go back to the videos i sent you and and see this actually happening in the illustrations they do a pretty good job the diaphragm contracts and moves downward okay meanwhile you also have ribs ribs and intercostal muscles that are on the sides of your uh of your uh rib cage okay now they don't show it to you that well here but they are showing you by the way of arrows so they're not illustrating it uh but if i wanted to draw them men the ribs would be out here sorry they're supposed to be on the outside okay and there are uh intercostal muscles that are in between okay so i'm just doing this for illustration purposes okay but what else happens when you inspire diaphragm contracts and moves down good two the ribs expand ribs expand and go up and outward okay correct and that's due to the contraction of the external intercostal muscles okay so you've got two contractions taking place when you inhale your diaphragm contracts and moves down your external intercostals contract and they pull the ribs as you see in this diagram here okay they pull the ribs out and up one of the videos described as sort of like the handle on a bucket that when you have a bucket with a handle on it that goes around like this when you pull the handle up okay the the circular handle basically goes up the way your ribs would okay so your ribs are here and then they go up and out as your sternum also is elevated and pulled up by various types of muscles so that's inspiration but wait a minute we didn't finish when your diaphragm goes down when your ribs get pulled up and out the result is there's a lower intra plural pressure which causes air to move into your lungs so really all this is happening is to change pressure and you know that air is always going to move from high pressure to low pressure so that's what happens here ribs go out diaphragm goes down the result is low pressure inside the lungs and so air has to move in as this blue arrows are showing okay now not that you have to know details but just know that the air is always moving from high to low sounds like diffusion but this is air pressure instead well guess what happens when you exhale i'll put that on the side expiration fancy word for exhaling well what do you think the diaphragm's gonna do it just contracted hint and move downward so during expiration what happens diaphragm will relax relax and go back which way it'll go back to its curve right so it's going to be normal yeah it's going to go back to normal so basically normal means it's going to go back upward upward right and go back to its curved shape your ribs let's just talk about the external intercostals external intercostals will also what relax relax and they when they relax what are the ribs gonna do so ribs will go back which way that's right they're gonna go back inward and think of the bucket handle down and down okay the result now that the ribs go say picture it now that the ribs are going in and the diaphragm is going up the result is going to be result maybe i should have put result before result there's going to be a higher intra plural pressure now i know in some of the videos they use different words they sometimes call it intrathoracic pressure intrapulmonic pressure it doesn't really matter as long as it's intra plural or intra pulmonic or intrathoracic to talk about the pressure in your chest whether it's inside the lungs or slightly outside the lungs it really doesn't make a big difference but it's the pressure inside so if the pressure inside has it happens to be higher higher interpol uh intrapleural pressure causes the air to be pushed out and that's your exhale okay and that's what you see in this diagram right here okay i see the ribs going in i see the diaphragm going back up so wouldn't that make sense that the change in pressure is going to make it higher on the inside and higher on the inside just means higher than outside air so if it's higher than the outside air that means out here it might be constant okay it's going to be generally lower but it's still the same number i don't know if numbers if you're a numbers kind of person but if you are if you need things to make sense to you this is what i'll say outside pressure is always 760. that's air pressure so when your lungs lower the diaphragm and increase your ribcage that means the pressure in here is going to be more like 756. so you see air is going to go from high to low but when your ribs go back in and your diaphragm goes up well then the pressure inside might be 764. and if the pressure inside is 764 it's higher than outside so that's what makes the air go out so air pressure changes is what actually causes you to inhale and exhale okay and that's what those videos are trying to show you what causes the inhaling and the exhaling okay now the regulation of this has to do with the medulla and the pons and that was another video but we'll get to that on wednesday so let's just finish gas exchange so so far we know how we breathe we got an idea how we breathe with the action of our diaphragm and our intercostal muscles we've got that there if there's any force breathing that needs to take place there's other muscles that are involved also let's take a look at those muscles for a moment so the muscles of inhaling i thought i just cleared this hard sorry there we go so these are the lungs at rest when the air pressure inside a 760 and the air pressure outside of 760. they didn't put any numbers in this but there's a nice diaphragm curve okay now here here's the balance but we're not going to try to interpret the graphs the graphs are a little crazy i like this diagram now it shows you and you can make a list if you like okay so up close well maybe not up close maybe it's better over here okay so the muscles for inhaling the muscles for inhaling are the diaphragm and your external intercostals those muscles contract when you inhale okay supplemental muscles when you have to take a deep inhale so you could say these are additional muscles so these are your normal muscles the first two i mentioned is normal breathing but if you have to go take a deep breath well then you need the help of other inhaling muscles the sternocleidomastoids help lift up your rib cage your scalenes help lift up your rib cage there are other muscles that help you to breathe in so when you're breathing heavily you have the pectoralis minor muscles right here that also help to pull up your rib cage so that's the difference between normal breathing and breathing when you're running those are the big muscles that increase your ribcage by doing what you see in this picture over here okay elevating your ribs so these are supplemental muscles during forced breathing when you're exhaling when you're exhaling normally these are the muscles involved you might say well i don't get it it's the same muscles no no no remember the difference is when you exhale your diaphragm is involved but it's involved in a passive way it relaxes during exhaling okay and the same thing is true of your external intercostals they relax during normal exhaling but when you're exhaling forcibly in other words blowing out birthday candles blowing out a pull toy when you're blowing out air when you're exercising now you're pushing air out of your lungs well in that case you need the supplemental muscles of exhaling and i didn't want to do that either all right i switched to green but it should stay black what i want for green is you're exhaling muscles and that would be your internal intercostals your transverse thoracic muscles and what you don't see here okay would also be your abdominal muscles so we're going to add that to the list contract during forced exhaling okay and that that's what's involved in all of your gas exchange the different muscles that are involved okay so inhaling pull the ribs up diaphragm goes down and these are the muscles that are involved if you want to exhale diaphragm goes back up ribcage goes down but if you want the ribcage to go down faster you have your internal intercostals that are going to pull your diet your your ribcage in faster they pull in and your abdominal muscles they're going to push the diaphragm up faster that's what your abdominals are for okay if you put your hand on your belly right now okay we're closing our class but put your hand on your belly right now if you relax and take a deep breath in deep breath you should actually feel your abdominals going out you're taking a deep breath in that's because your diaphragm is going down pushing your gut out now do the opposite okay blow the air out of your lungs really slowly and keep blowing out until you can't blow out anymore and watch what your abdomen does when you no longer can speak you know you took all the air out of your lungs but did you feel your abdomen going in your abdominal muscles contract not to push on the lungs but to push the diaphragm up and indirectly help air get out of your lungs okay so we're going to close right here this is the physical changes that happen during breathing and again you can look at those videos before wednesday just to get a review on this on wednesday we're going to finish up the gas exchange and the physiology of breathing and we should be done with chapter 23. okay any closing questions i have a question sure um so when we are inspiring uh the muscles associated with that are the external intercostal muscles and they contract when we inspire and same with the diaphragm contracts when we inspire yes when we inspire right these two are contracting and then when we have heavy breathing we use the supplemental muscles of inspiration which are the sternocleidomaester gladomastoids the scalenes the pectoralis minor and all three of those contract during ins heavy inspiration yes and include the serratus anterior on your list okay okay they all do the same thing they're contracting and somehow in different ways they're lifting the ribs up heavier so just think of like when you go your shoulders go up like you're really surprised you know you know everything basically everything is pulling your ribs up in a hurry when you're taking a deep inhale or continue all right and then with x x uh expiration we have the external intercostal muscles and the diaphragm both relaxing but when it comes to heavy breathing when we use the supplemental muscles of expiration we have the internal intercostal muscles the transverse thoracics and the abdominal muscles but do all three of those contract yes okay see that now they're contracting to push the diaphragm up and to pull the ribs down the big one that pulls the ribs down is your internal intercostals they oppose the externals so your internal intercostals really pull your ribs down you can see the striations here in the illustration they're in a down position okay your transverse thoracics also do that but they do that from the inside they're pulling the ribs down but these are the main ones right here okay thank you so much you're welcome any other questions okay so let me stop the recording