[Music] hi it's Mr Anderson welcome to my podcast on the respiratory system function of the respiratory system is basically to take in oxygen and then get rid of carbon dioxide and right here in Montana at around 5,000 ft that's no big deal but if I were to climb Mount Everest the higher I go the less oxygen there's going to be and that's a real limit to uh our ability to climb very high and so it wasn't until 195 53 that uh Sir Edmund Hillary and Tenzing norg finally climbed Mount Everest for the first time and you can see tenzig norg right up on top the first photo ever taken from the top of Mount Everest it wasn't until 1953 but if you can't see on his back there's a huge canister that contains oxygen and that leads into his mouth because they had to take oxygen with them and so it wasn't until I think 1971 that somebody was able to climb all the way up Everest without using oxygen and that they do that by going up to a base camp move up higher move down move higher move down move higher move down and so their body is starting to accommodate to that change in the uh elevation and even that you're pretty much dying at the top uh because of that lack of oxygen and so basically animals have figured this out in a number of different ways if you're a worm your respiratory surface is actually going to be your skin you're absorbing oxygen and getting rid of carbon dioxide Through Your Skin So their skin has to be moist and they have to have a large surface area if you're an insect you use things called spiral so basically there are holes on the side of an insect that go to tubes that go to more tubes and more tubes and more tubes and more tubes and an insect actually has tubes that almost go all the way down to the level of um cells and so you have to have a huge surface area is one thing you need and then it has to be moist is another thing you need and so the two big things I want to talk about are gills so gills is a way that fish has have solved this problem uh and then lungs and that's the way that we've solved it and so what's the difference between fish and us well fish live in an area that's really really moist so they don't have to worry about that and so their gills just sit right out in the water but they also live in an area where there's not much oxygen at all and so they have to have a very efficient way of exchanging oxygen us well we have to fold our lungs inside our body so we can keep them moist um but there's so much oxygen in the air relative the amount that's in the water that we don't have to be as efficient so how efficient do the gills actually have to be in fish they can reclaim something like 80% of the oxygen that's in the water so they're really really efficient we're not even close to that and the way they do that is they use something called countercurrent gas exchange and so basically as the blood flows through the gills the blood is going to flow like this so all the blood is going to flow in this direction and then it's going to flow out the other direction so in the gills it's going in that direction and then it comes out in the other direction but the water is going to flow in this direction and so what you have is the blood flowing in this direction and then you have the water flowing counter to that and so as they go like that it pulls water in over their gills but the blood is moving in opposition to that Engineers use countercurrent exchange quite a bit but basically what is it doing well if you think about this this is going to be the dirtiest of blood down here and then it's going to get clean cleaner and cleaner in other words it's going to get more and more oxygen but what it's doing is as it gets more and more oxygen it's meeting water that's more and more fresh in other words it has more of the oxygen present and so by putting blood in the opposite direction they're really efficient at at at getting that oxygen outside of the um water now us we don't have that problem we do have a problem with moisture and so we actually have to fold our gills inside our body they're not gills but we fold our lungs inside our body and so we have a trachea that leaves down into bronchus and then bronchioles all the way down into the Alvi one thing that's important to note is that it goes in and then that's it in other words it's oneway flow when we breathe in goes in and then that's the end of it and so if you take things in like if you smoke all the material that comes in is going to go into your lungs and then there's no out and so if you breathe a lot of Cal dust it's going to go in and then it gets stuck in there or a as spest just goes in and gets stuck and so the lining of the trachea lining of our respiratory system has these cyia on them and so basically what happens is those little hairs are going to move material out of your body so you can cough it up and eventually swallow it another cool thing about this is that it really looks let's even go to this level it almost looks like a tree upside down and so basically what's happening is that we are increasing the surface area by having the trachea go to the bronchus and then the bronchioles and and they just keep branching and branching and branching again why are they doing that they're doing that to increase the surface area and so your lungs are small but I remember once reading that they have the surface area of a tennis court and so by having that large surface area we can absorb even more oxygen but the functional units of the lungs are the Alvi so if we get way to the end of these tiny bronchioles we eventually have these little sacks they're called Alvi they're they're covered in a single layer of cells called Simple squ cells and they have a tendency to just kind of fold in Imagine a tiny balloon that that's that small it would just kind of fold in on itself and so they have to have these chemicals called surfactants on the inside that kind of lubricate it so it doesn't close up that's one of the reasons why uh premature babies have to be in a ventilator because they haven't really developed that surfactant yet but wrapped around all the alvier we have these capillaries and so basically what's happening is that we're taking oxygen from the um from the the Alvi and we're passing that off onto these capillaries and then we're getting rid of carbon dioxide that's the function of the Alvi now how does breathing occur um breathing occurs using the diaphragm muscle you've dealt with a diaphragm if you've ever had the hiccups because that's just a spasm in the diaphragm muscle but basically what happens is we have the diaphragm muscle here and then as that contracts and pulls down then we have air moving in so it's like you had a jar with a balloon on the inside of it with rubber on this side and if I were to pull right here if I were to pull that down basically it's going to inflate the balloon because air is going to move in through here so I decrease the pressure and then as I relax the diaphragm it's going to go like that and as I contract the diaphragm it's going to move up like that it's very important that then just like this jar that this is very intact here we have to make sure that this whole thoracic cavity is intact so we can create that pressure okay so let's get to the level of that oxygen exchange so how do we get oxygen in well basically if you were to look here in the capillaries let's imagine that this out here is the space in the Alvi so now we have air coming in so we have air out here basically what's going to happen is these red blood cells as they move through the capillaries that oxygen that's inside the uh Alvi is going to move in and so these red blood cells are almost in direct contact with the capillaries now where is the oxygen going to be stored we have a chemical called called hemoglobin hemoglobin is a protein and that's stock full inside all of our red blood cells that's why it's red so basically inside the hemoglobin we have these iron molecules one there one there one there one there and that iron is going to bond to the oxygen that's found inside the air and so why is it red it's because it literally is rusting the oxygen is attaching to the iron and it's giving us that red color and so that's where the oxygen is going to bind it's going to bind to that heem group or the iron inside the hemoglobin what about the carbon dioxide well the carbon dioxide is not really contained within the red ball itself itself basically what it's doing is it's being converted to bicarbonate so we're converting that carbon dioxide with water to this bicarbonate and a lot of that bicarbonate will actually be right here inside the plasma of the blood some of it will be in the blood cell but most of it's in the plasma when we get here to the Alvi we've got enzymes that control all of this then that's going to release as carbon dioxide so carbon dioxide goes back into the Alvi then we breathe that out we take in more oxygen over and over and over again and so that's the respiratory system it doesn't work if we don't have the circulatory system but we'll get to that in the next podcast and I hope that was helpful