Biological sciences, Health

The Respiratory System, an overview

Respiratory System by Mr. Anderson: Hi it’s Mr. Andersen and welcome to my podcast on the respiratory system. The primary role of the respiratory system is basically to take in oxygen and then get rid of carbon dioxide.

The respiratory system is a Right here in Montana at around 5,000 feet, that’s no big deal. However, 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 our ability to climb very high. So it wasn’t until 1953 that Sir Edmund Hillary and Tenzing Norgay finally climbed Mount Everest for the first time, and you can see Tenzing Norgay 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. So it wasn’t until I think 1971 that somebody was able to climb all the way up Everest without using oxygen, and they do that by going up to a base camp move up higher move down move higher move down and so their bodies starting to accommodate to that change in the elevation, and even that you’re pretty much dying at the top because of that lack of oxygen. 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 spiracles 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 cells and so you have to have a huge surface area is one thing you need and then it has to be moist as another thing you need and so the two big things I want to talk about our gills so gills is a way that fish has have solved this problem and then lungs and that’s the way that we’ve solved it 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 so they’re 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 bodies so we can keep them moist 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 to 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 counter current 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 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

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Engineers use counter-current 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 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 or in other words it has more of the oxygen present and so by putting blood in the opposite direction they’re really efficient at getting that oxygen outside of the 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 leads down into bronchus and then bronchioles all the way down into the alveoli one thing that’s important to note is that it goes in and then that’s it in other words it’s one-way 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 and so if you breathe a lot of cold us it’s going to go in and then it gets stuck in there or asbestos goes in and gets stuck and so the lining of the trachea lining of our respiratory system have these cilia 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 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 trachy to go to the bronchus and then the bronchioles and then 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 alveoli.

If we get way to the end of these tiny bronchioles we eventually have these little sacs they’re called alveoli there they’re covered in a single layer of cells called simple squamous cells and they have a tendency to just kind of fold in and 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 to kind of lubricate it so it doesn’t close up that’s one of the reasons why in premature babies have to be in a ventilator because they haven’t really developed that surfactant yet but a wrapped around all the alveoli air we have these capillaries and so basically what’s happening is that we’re taking oxygen from the UM from the alveoli and we’re passing that off onto these capillaries and then we’re getting rid of carbon dioxide that’s the function of the alveoli now how does breathing occur on 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 for her to pull that down basically it’s going to inflate the balloon because 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 can track 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 alveoli 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 alveoli 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 hemoglobin.

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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. That iron is going to bind to the oxygen that comes from the air. So why is it red? It is because it literally is rusting. The oxygen is attaching to the iron. It’s giving us that red color. So that’s where the oxygen is going to bind. It’s going to bind to the iron inside the hemoglobin. What about carbon dioxide? Well, the carbon dioxide is not really contained within the red ball itself. Basically, what it’s doing is that 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 is in the plasma. When we get here to the alveoli, 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 alveoli, and we breathe that out. We take in more oxygen over and over and over again. 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 pie. Yes, and I hope that was helpful.

As found on Youtube

See crash course on the airway

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