Gas Exchange and Breathing

by Jason Amores Sumpter
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Hi. In this video, we'll be talking about gas exchange and respiratory physiology. Now, gas exchange allows animals to get the oxygen that they need for cellular respiration, as it's the final Elektronik sector in the electron transport chain. And it also allows them to get rid of Waste Co two from their metabolism. Now small animals can perform gas exchange across their body surfaces due to their high surface area to volume ratio. And you'll see this in organisms like Platt hell mentees, you know, flatworms, that sort of thing. Now, for larger animals, we're going to need respiratory organs that air specialized to allow us to perform gas exchange with lungs are going to be the example will be looking at. And, uh, essentially these organs provide the surface area and necessary for gas exchange. And here you can see, um, the Malian, specifically human respiratory anatomy. We have air that will enter through Well, I guess the mouth or the nose. Really? Either way, it's going to go down the trachea and split into the bronchi, which will diverge into bronchial Z all through the lungs. And of course, those will end in Alvi, Eli and, uh, in the Alvey lie. That's where the magic happens. That's where gas exchange occurs. Oxygen that is inhaled is going to move into the bloodstream. Uh, in those capital Aries that's surround the Alvey lie, and carbon dioxide is going to move from the blood stream into the Alvey. Lie to, of course, be exhaled. Now, where these molecules air going to and from is cells and specifically mitochondria in cells. So theocracy gin is going to be transported through the blood and delivered to tissues, where it will make its way to the mitochondria to act as the final electronic sector in the electron transport chain. And of course, CO two from the mitochondria is going to be transported into the blood and out into the valve. Eli to be exhaled. And that CO two is coming as a byproduct of metabolism. Um, you know, specifically like the citric acid cycle, where those, uh, carbon compounds are broken down and the carbons are oxidized and given office CO two. So respiratory organs provide that surface area for gas exchange. But we need a way of getting air in and out of the respiratory organs. That's where this lovely muscle the diaphragm comes into play. Uh, the diaphragm is what we use. Of course, not everyone does it like humans or mammals Dio And, uh, we actually will see that there are, you know, uh, different types of ventilation and we're gonna look at positive pressure and negative pressure. Ventilation real quick. So essentially positive pressure, not just ventilation, but in general, positive pressure is like a form of pushing. It's like a squeezing, pushing force. Negative pressure is more like a pulling force. Um, you know, think about like, for example, you know, taking some container and and sucking the air out of it Like, I don't know if you've ever done this, but like you take a glass and you stick it up to your mouth and just suck all the air out of it and it just stays stuck to your face. That's because of that pulling force, that negative pressure that is pulling it on to you. So, with positive pressure, ventilation, we have air pushed into the lungs. This is like what frogs do. That's why they inflate that big pouch in their mouth. And then they actually squeeze that air through positive pressure down into their lungs. We, on the other hand, we use our diaphragms, and what we do is basically we jump out of the way Here, here's our diaphragm. That muscle, we pull it down and at the same time we draw out our ribs. And by doing this, um, we create negative pressure in this area known as the thoracic cavity. So, basically, by expanding the volume of that cavity, we create negative pressure, and then all you really have to do is just open your mouth and the air is gonna come shooting into your lungs, right? It's gonna get pulled in. And when we exhale, we just relax. That diaphragm, uh, relax our ribs and they moved down And that, uh, you know, changes the volume of this cavity and causes the air to be exhaled. So we breathe. Using that system, it's called negative pressure ventilation. It involves negative pressure, sort of pulling force, and we rely on our diaphragm and the movement of our ribs to generate that negative pressure. With that, let's flip the page