Functional Anatomy of the Lower Airway (Nursing)

00:00 So let's break down the trachea. We've nicknamed it the windpipe. You hear a lot of people call that like "Ohhh got something stuck in my windpipe." That's what we're talking about. But look at our graphic. Okay, it looks like a lot of words but it's really well done to help you have this clarified in your mind. Now look there, we have it labeled the larynx. Right? And that's equally right around where your Adam's apple is. Now an Adam's apple is much more predominant in male patients than it would be in female patients, but you get the idea of what an Adam's apple is. Now you have the tracheal cartilage. Remember that's going to help keep that kind of stiff and keep it open, that's a good thing. The trachea where it splits apart, we've got the primary bronchi. So the bronchi are the bigger tubes, remember they've got that cartilage in them that helps keep them open and the primary bronchi go into both the right and the left lung. And then you'll see we have the secondary bronchi. That just means same tubes, getting a little smaller, little further into the lung tissue. Now on the left side, we've labeled it for you larynx, trachea and then you just see that labeled on there on the lung. So, pause for just a minute before we walk through the key points. Pause the video, take your finger, trace over those different structures, make sure you're very clear where they are. This will make it much easier going through the rest of the video. Okay, that was time well invested. Now that you have that anatomy refreshed in your mind, let's take a look at some of the key points. So that trachea or windpipe is about 4-5 inches long or 10-12.5 cm. Now it's a cylinder and it's less than 1 inch or 2.5 cm in diameter. That's why if someone has a foreign object lodged in there like food or if a child, whose windpipe is even smaller, swallowed something like a toy you can end up in a real life threatening emergency. Now, the trachea or the windpipe sits right in front of the esophagus so that's important to keep in mind when you're dealing with anatomy that the trachea is right here external in the neck. Right? So it's in front of the esophagus. It also begins just under the larynx and you can see that in the picture and it runs down behind the sternum. Okay, so now we're pretty well oriented to the trachea, to the windpipe, and the different parts of the airway initially. Now the trachea has these incomplete rings of hyaline cartilage and smooth muscle. That's good, helps it to be stiff and strong and that's a good thing. It divides, as you see in the picture, into those 2 smaller tubes, we call them bronchi.

02:56 There is 1 for the right lung and 1 for the left lung and those go down deep into the tissue of the lungs. Now, let's look at how the cells, the cilia, the cartilage, and the cough, how this all works because the trachea is lying with this mucus-producing goblet cells in these ciliated epithelia. So epithelia is a type of the cell but they also have cilia. So, why is this such a cool protective feature? Well, the smooth muscle can contract and that decreases the trachea's diameter and it adds force to it in exhale. Why is that important? Well it's pretty impressive that you need to get something out of that airway whether it's a foreign object or just a bunch of mucus field, right, that needs to be expelled out. Then you wanted to be able to contract down, it help add force to the exhale, we call that a cough. So the forced exhalation helps us get rid of mucus when we cough. Well, no one likes to really cough that stuff up, but here's why it matters. You know how it protects. Right? We did talk about how mucus keeps that lining nice and smooth and moist so it doesn't dry out. It also collects things, right, and moves it up towards with a whole purpose of getting it out of your body. So coughing is good, we need to clear excess mucus, we want to clear particles and things that don't belong in your body so a good, strong, and cough is really important. After a patient has had surgery and they have been immobile for a while, we want to make sure we turn cough and deep breathe with them because that helps keep those airways opened and functioning well. So remember those cilia.

04:38 I just want to point that back out. We talked about it when we remind you again it's those cilia that move the foreign particles that are trapped in the mucus up toward the pharynx. Now picture in your mind where is that. Right. That's in the back of your throat and then it can be coughed out and expelled from the body or sometimes people could swallow it. Right? The epiglottis flaps back and forth, it's up in the pharynx, they can also swallow it down in their stomach and then it's going to be eaten up by the gastric acid. I know that's not really socially acceptable to talk about that, but that is one mechanism and the way it can function. Now we're comparing the right side to the left side, they are not identical twins. The right lung is larger than the left and the right has 3 lobes, the left has 2 lobes. Now, the reason this is it will be easier for you to remember if you look at the orientation of the lungs and the heart.

05:33 You see that the left side is smaller because that's what its job is is to accommodate the heart to make room for the heart. So the left lobe has fewer lobes, it has 2; the right has 3; and the left side is a little bit smaller because it's making room for your heart.