Organization of the Body: Thoracic Cavity - Video Tutorials & Practice Problems
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concept
Organization of the Thoracic Cavity
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We've been talking about the different cavities of the body and the different membranes. But now we want to take all that information and put it together, figure out where everything is located relative to each other. So we're gonna start with the thoracic cavity and we're gonna say that thoracic cavity remember is the space superior to the diaphragm, the space within your rib cage, there's a few different spaces in there. We're gonna talk about the ones that you already know first. So first up, we have the plural cavities and remember those are serra membrane bound. Remember cerus cavity is the space between that double layer membrane where the serous fluid is located. The plural cavities are made up by the membrane, the pleura and these surround the lungs. So if we look over at our anatomical model, we can see a frontal view of the thoracic cavity that's color coded and in blue on each side, you see a shape of the lungs and that's where the plural cavities or the lury and the lungs are all gonna be located next. I'm gonna jump down to the bottom of our list because that's the o other one that we've already learned, we have the pericardial cavity, the pericardial cavity also serous membrane bound made up by the membrane, the pericardium and this is gonna surround the heart because remember that cardiac means heart. So again, if we look at our frontal view here, we say that see the shape of the heart here right in the middle of the thoracic cavity. We also though have this shape that's in orange that I'll outline here. And this is the space between the two lungs. And you'll notice that the heart and the pericardium are actually in that space. This space is called the mediastinum. And the mediastinum is just the space between the plural cavities. This is gonna contain a lot of different things. For example, we just said the heart and the pericardial cavity, the esophagus, the trachea, the thymus, anything that's between the lungs or between the pleura is gonna be in the mediastinum. Now, importantly, this is not technically a cavity. It's just a space in the thoracic cavity where some stuff is located. So if we wanna really say everywhere that the heart is, we could start with the heart, right? The heart is gonna be surrounded by the pericardium. And within the pericardium is the pericardial cavity which also surrounds the heart. The heart and the pericardium are located in the mediastinum because the mediastinum is the region between the lungs and the heart is between the lungs. The mediastinum is located within the thoracic cavity. The thoracic cavity is part of the anterior body cavity. Ok. That's a lot of different layers. But we're gonna practice it some more going forward and then we'll talk about the abdominal pelvic cavity. I'll see you there.
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example
Organization of the Body: Thoracic Cavity Example 1
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This problem tells me that the esophagus is in the superior section of the digestive tract running from the pharynx, the back of the mouth to the stomach. It runs through the middle of the thoracic cavity behind the trachea and the heart and through the diaphragm where it meets the stomach and the abdominal cavity based on that information fill in the table below. Well, in the table, our first column says location and the locations it gives are the thoracic cavity, the pericardial cavity, the plural cavity and the mediastinum. And then it asks, is the esophagus found inside each and if no, give a directional term indicating its relative location. So let's start with the thoracic cavity is the esophagus in the thoracic cavy. Well, it says right here, it's in the middle of the thoracic cavity. So I'm gonna say yes to that because it's inside. I don't need to give a directional term. Next, we have the pericardial cavity is the esophagus in the pericardial cavity. Well, the pericardial cavity is a cavity made up by the pericardium, the membrane that surrounds the heart. Remember the cavity is the space between those two layers of the membrane, the esophagus is not in there. So I'm gonna say no, where is it relative to the heart and the pericardium. Well, it says right here that it is behind the heart. So we have a term for behind in the body and that is posterior. There's also note you could write deep, right? It's deeper into the body than the heart. So the esophagus is deep to the heart. Next, we have the plural cavity is the esophagus in the plural cavity. Well, the pleural cavity made up by the pleura a membrane that surrounds the lung. No, it is not in there. So I'll, right. No, but where is it relative to that cavity? Well, here it just says plural cavity. It just lists one. It doesn't say the plural cavities, doesn't tell me left or right. But regardless either one, the esophagus is going to be medial towards the middle of the body compared to a plural cavity. Now, if it said plural cavities or the lury, then I could say it is also intermediate. Remember, intermediate means between two things on that medial lateral scale. Finally, we have the media steinem is the esophagus in the mediastinum. Well, the media stum is this orange region here, right? This orange region is the space between the lungs. The esophagus is running down the middle of the thoracic cavity. So it's absolutely in the media stum because it's in, I don't need to give a directional term. Ok. With that, I'll see you in the next video.
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Problem
Problem
Which term describes a structure that is directly superficial to the heart?
A
Thoracic
B
Pericardium
C
Mediastinum
D
Pleural cavity
4
Problem
Problem
How does the structure of the pleurae aid in their function?
A
Serous fluid reduces friction.
B
Rigid shape gives structure to the flexible lungs.
C
Large surface area helps gas diffuse.
D
A & C are correct.
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