Hello and welcome to the PowerPoint presentation for the respiratory system for 2402 Lab. This is section 22 in your lab book. All right, so this is kind of an overview, basic functions of your respiratory system. The main job is to get gases into your blood and the blood then and then those gases can go to your tissues, but there are several other functions as well. So moving your air, the air in and out of your lungs, it has a technical name as you see on a table on page 106 and that's called pulmonary ventilation so that actual breathing is called pulmonary ventilation on the way into your respiratory system the air is filtered with the hairs and mucus in your nasal cavity and mouth not the hairs in your mouth but the mucus the air is moistened and it's warmed especially if you're somewhere cold like we don't really need to warm it around here Then when gas is exchanged between the air that's in your lungs and the capillaries that supply your lungs, that process is called external respiration.
So when you have a cap, like an alveolus, here's some alveoli, and here goes a blood vessel right there. So the oxygen is going to go into the blood and CO2 is going to come out of the blood into those alveoli. That process is called external respiration.
Now, you might think, well, why is it external? Because it's in my lungs. But really, it's a continuous pathway from the outside air down here into the alveoli.
So it's happening with air, with oxygen that's technically outside of your tissues. Now, once it's absorbed into the blood and your blood takes it down to the cells, the process of gas exchange there, where the blood's going to go... sorry, the gas is going to go from your blood into your cells or from your cells into your blood.
That's called internal respiration. Lastly, when the oxygen is used by your cells, that's called cell respiration. And that's the process where you do glycolysis and Krebs cycle and the electron transport chain to get ATP.
You also use your respiratory system for sound production. And that's a really important function, believe it or not. Humans have gotten to be as powerful as they are partly because they are able to communicate with each other so well.
Moving on. The pleurae. A pleura is a membrane associated with the lungs.
The serous membranes that we learned about before have location-specific names. The serous membranes of the lungs are called the pleurae. So you have the parietal pleura, which lines the inside of the body wall.
So it'll line the diaphragm and the inside of the ribs and so on. The visceral pleura is the lining that lines the actual lungs themselves. There is a pleural cavity in between the visceral pleura and the parietal pleura.
filled with something called pleural fluid. Pleural, it's easy to say. Pleural fluid. And this stuff allows you the lungs and the parietal pleura to slide along each other so they don't stick.
They don't get, you know, there's a lot of movement of your respiratory system when you're inspiring and expiring and you don't want those delicate membranes to adhere to each other. If you ever have one of those sharp pains in your ribs when you're taking a breath, Now there's a good chance that that sharp pain is caused by a sticking of those two membranes together. Usually that ends up with me like punching myself in the ribs and it goes away, but who knows.
Because that fluid is a non-compressible, that liquid is non-compressible, when your lungs expand, the fluid that's in between the ribs and the lungs drags the lungs with them. So as you... inspire as you breathe in your volume of your lungs gets bigger and the lungs get larger which causes the volume to drop I'm sorry causes the pressure to drop and that's that's what we see here in Boyle's law which I'll talk about on the next page so it's not a very confusing and everybody gets like oh no math but it's fairly simple math pressure you see down here in that formula pressure one times volume one equals pressure two times volume two and I'll explain that with the next slide Okay, a couple of more summary points here.
Intrapleural pressure. So intrapleural pressure means the pressure in here, in this pleural cavity. Intrapleural pressure is less than intrapulmonary pressure. Another name for intrapulmonary pressure is intraalveolar pressure. So what you're thinking about there is this pressure.
So the air pressure in your lungs is greater than the... pressure exerted by this fluid. So what that causes is a net outward pressure of the air inside of those lungs.
So the lungs stick to the walls of the thoracic cavity. When you have your mouth open or your nasal cavity open so that it's continuous with the atmospheric pressure, they're equal to each other. So whatever the pressure is in the atmosphere is the same pressure in your respiratory system.
Your long is at rest, at least. Next slide. All right, so here's Boyle's Law. Now again, P1V1 equals P2V2. Let's look at this diagram on the right first, okay?
So this one over here. You can see that the first container has a volume of one liter and whatever, a pressure of 100 millimeters of mercury. If I decrease that volume by...
one half. So I make it, instead of one liter, I make it 0.5 liters, pressure double. So when I cut the volume in half, I double the volume. If I cut the volume by one tenth, if I made it 0.1 liters, then P2 would be 1,000 millimeters of mercury. So all you have to do is solve for the variable that you want to solve for to determine whatever P1 or P2.
And if you have any questions on that... please stop by my office hours if you need me to run through it but it's a simple solve for the the the uh the variable now think of this is kind of this is what you'd call a closed system over here this is a closed system because the there's no air getting in and out right so when i decrease that volume pressure goes up because the air doesn't have anywhere to go but if i put an opening in here let's say and i decrease the volume Well the pressure would go up which means that the air would go out. If I then increase the volume pressure would go down in here which means air would go in.
So this is how our lungs work. That's how your respiratory system works. Over here when I increase the volume by expanding my ribs or depressing my diaphragm it's going to cause the pressure in here to go down.
the atmospheric pressure out here stays the same so air kind of blows down into your into your lungs conversely if i decrease that volume by relaxing my ribs and relaxing my diaphragm the pressure inside of my lungs is going to go up and air is going to blow out now we call this a negative pressure ventilation because in order to get the air in i just gotta increase the volume, which decreases the pressure. So that pressure differential is caused by a negative pressure in my lungs. Now that's opposite.
You guys may have heard about ventilators recently due to COVID, where they'll have to put someone on a ventilator. What they do is they put a tube down their throat, down their trachea, and get it right to the base of that trachea where it splits in two, kind of like this. And that tube then will push air into your lungs.
So it's not like the volume of your lungs gets bigger causing a lower pressure. You're just amping up the pressure outside of here and forcing air into the lungs which you know in an emergency can get the oxygen into your blood but it's not pleasant for the soft tissues that your lungs are made of. And the last slide this is a quick one.
A quick presentation, I hope. A little bit of a summary here. I said I have it as respiratory system boils law. I just forgot to change that heading, but I'm not going to start over now.
Some of the muscles involved here. So let's see. I'm going to just cross that off right now.
Let's go with a different heading. We're not going to do that. We'll say respiratory system muscles.
I write like a child. So we see that the muscles of inspiration, and inspiration is the technical term for breathing in, inspiration is active, as I've written there, which means that we actually contract muscles to do so. The primary muscles are these down here, the diaphragm. and the external intercostals.
Those cause the diaphragm depresses, causing the volume to get bigger, and the external intercostals cause the ribs to expand, likewise increasing the volume. If you really have to take a super deep breath, you can engage some of these accessory muscles and, you know, raise your shoulders up and your arms kind of change position. So just about when you're ready to blow out the birthday cake, right? Everybody, nobody goes, well, you can't see me, but they take a super breath. They go, right?
So it's going to engage all those other muscles. Now I want you to try this once. Take a really deep breath and hold it for a couple seconds and now let it out. So what did you have to do to let it out?
All you had to do was relax. So normal breathing is, expiration is passive. So you just, you breathe in, takes energy, relax, air goes out. Now if you're going to have forced expiration or here they call it active breathing forced expiration sounds better then you're going to engage your abdominal muscles and your some accessory rib muscles the internal intercostals so to really compress that thoracic cavity forcefully so when you want to blow out a birthday cake or blow out blow down a little pig house then you'll you'll you'll use this forced expiration and engage these other Alright, well be sure you look at the videos that I have posted.
I think there's seven of them and the photographs that have questions and Notations on them and good luck out there. Stay safe