Organization of the Body: Serous Membranes - Video Tutorials & Practice Problems
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1
concept
Serous Membranes
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4m
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We just talked about how we can divide the anterior cavity into some smaller body cap, but we can divide it even further. We're gonna say that the body cavities are further divided by serous membranes. So these serous membranes are sometimes called the serosa. These are thin sheets of tissue that form a double layer membrane and this double layer membrane, these two layers are gonna wrap many organs or as we're calling them the viscera, the organs of the thoracic and abdominal pelvic region. So you want to imagine the serous membranes like pushing your hand into a soft balloon. And so we have this diagram down here of a hand being pushed into a soft balloon. And you've probably seen this in your textbook or maybe in a lecture, I'm gonna go into this analogy in a lot more detail in just one second. But first, I want to just identify the different layers of this two layer membrane. So first off, we're gonna have the visceral layer and that's gonna be the inside layer. It's gonna be attached to the viscera makes sense, right? And remember we said the viscera are the organ. So the inside layer is attached to the organ, it surrounds. Now, the parietal layer is the outside layer and that's gonna be attached to the body wall. And the word hori comes from the Latin meaning wall. So let's start by looking at the heart over here over here, you can see the heart, it's surrounded by this double layer membrane. And of course, it's cut away that the entire heart would be covered by this double double layer membrane. But we're looking at it in cross section. Now we see visceral layer and it has arrows pointing to this inside layer which I'm just gonna highlight in orange here. So the part touching and attached to the heart is the visceral layer. And then the part on the outside is gonna be the parietal layer and that part on the outside is going to be touching and attached to the body wall. So we have this analogy to try and make this clear. I wanna try and make it even more clear by acting this out for you. So for a balloon analogy, I'm gonna use a plastic bag. Now a plastic bag, two layers, one layer, two layers, that's a double layer membrane. Well, if you wanted to put an organ in a bag to separate it, you could just, I'll take my hand, I'll pretend my hands, my heart, I could put my heart in the bag. Now, importantly, organs don't go in the bag. There's gonna be some stuff that goes in the bag later on. But it's not or what we're gonna do is tie off the bag like a balloon. I can't get to the inside of the bag there. There's still an inside of the bag in there, but I can't get to it because it's tied up in clothes. So where does my heart slash fist go while I'm gonna punch the bag and wrap this bag around my hand? All right. So now my hand is completely surrounded by this bag. It's not in the bag. It's surrounded by two layers of the bag. One layer of the bag is touching my hand. That's the visceral layer. The other layer is on the outside here and would be attached to the body wall. That's the parietal layer. Now to make this even more real, I wouldn't just punch the bag. I would dip my hand in super glue first and then I would punch the bag. So that visceral layer of the serosal membrane is going to be firmly, firmly attached to my hand in the body. It's gonna be attached by connective tissue. I then take the outside layer, the parietal layer, I dip that in superglue and I'd attach to the body wall and pretend my other hits the body wall. So now it's firmly attached to the body wall again in the body that would be done by connective tissue. So my hand slash heart on the inside is glued there, the hand slash body wall on the outside is glued there. But importantly, part of this bag is not glued to anything. The inside of the bag is not attached to anything. So if my heart moves the inside of the bag can slide past itself. All right, we're gonna look at that concept in more detail in the next video. For now, we have an example to go over these different layers and I'll see you there.
2
example
Organization of the Body: Serous Membranes Example 1
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1m
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This example tells us that the lungs are surrounded by a serous membrane called the pleura. The image below shows the right lung and the plural membranes that surround it s label the visceral and parietal layers of the plural membrane. OK. So we see a picture of the right lung. We see the trachea coming down and the airways entering the lung. We don't really worry about that in this picture, what we're concerned about is this double layer membrane that is surrounding the lung. And we want to identify the two layers. So first off on the top line here, we have an arrow pointing to the outer layer. So remember that outer layer we said is gonna be fused to the body wall. And we said that in Latin, the word for wall had to do with parietal. So parietal layer is gonna be fused to the body wall, the outer side of the membrane, the inner side of the membrane here is gonna be up against the organ. And we learned this vocab word that the organs of the thoracic and abdominal pelvic regions, we call them the viscera. So if it's fused to the viscera we call it the visceral layer. All right, with that, we'll see you in the next video.
3
concept
Serous Cavity and Fluid
Video duration:
3m
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We just defined the cerus membranes or the choa and we identified the visceral and parietal layers of those membrane. Now, we want to talk about what happens between those two layers because that's where things get a little interesting. So remember the serous membranes are a double layer membrane. And we're gonna say that the cerus cavity is gonna be the space were sometimes potential space between that double layered serosa. So the space between the layers is the cavity, we say potential space because sometimes those two layers are just pushed right up against each other. So there actually isn't space between them, but they're not attached to each other. So you could, you know, blow them up like a balloon if you wanted to. All right. So what's in that cavity? What's in that space? What's in the space is serous fluid? So, serous fluid is the fluid found in the cerro cavity. Serous fluid is there for a really good reason, it lubricates the membrane. So organs can move easily. Now, this cavity isn't filled with a ton of fluid. For lubrication, you just need a little bit of fluid in there to get everything nice and slippery. So we're gonna return to our plastic bag analogy to think this through. So remember we have our plastic bag. This represents the serous membrane where it's gonna go around an organ. Remember our organ, in this case, my hand doesn't go in the bag that's in the cavity. The organ does not go in the cavity. We're gonna tie off the bank like it's a blue. Now that space inside the bag that I can't get to now because it's all tied off. That's the cavity. That's the cirrus cabinet. Now I was gonna sit uh take my hand, my organ dip it in superglue and punch the bag and wrap it around. So it firmly attached to that visceral layer of the membrane. Ok. So now think where's the cavity? Well, the hand is not in the cavity still, but the cavity is surrounding the organ. My hand, it's all on all sides of it. The prial layer layer is on the outside here. And we were gonna again like take my other hand, the body wall to dip that in super glue and attach it. So now the prial layer is firmly attached to the body wall. The visceral layer is firmly attached to the hand or the organ on the inside. But on the inside, there's this lubricating fluid. So when the hand moved and the organ moved, it slips around without any fun. And you may be wondering well, how much do organs move. Well, I don't know if you've ever seen a video of the heart beating, but that thing cranks. Right. It is just beating, moving all day long, 60 to 80 times a minute your entire life. And it's gonna be in this c doing that all the time. You can imagine if that cavity weren't there. If it didn't have that lubricating fluid, if you just rubbed your hands together, 60 to 80 times a minute, all day long, your entire life, you're gonna wear the tissue off your hands. It's gonna become incredibly painful. You don't want that to happen to your heart. I always say a chafing heart only should exist in a country song. All right. So that, remember the cavity surrounds the organ, the organ isn't technically in the cavity. What's in the cavity is the fluid that fluid lubricates. So that when you move your organs can slide around in your body without any issue, that example to follow practice problems after that. And I'll see you there.
4
example
Organization of the Body: Serous Membranes Example 2
Video duration:
2m
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This example tells us that the disease pleurisy causes an increase in serous fluid in the serosa surrounding the lungs. How do you think this might affect breathing? And we have this picture of a lung over here on the right. And the important thing is that we see this double layer membrane surrounding it. Remember, the inner layer is the visceral layer, the outer layer, the parietal layer and between those layers is the cavity and the cavity is what's filled with the fluid. So let's think if you got more fluid in that cavity, how would that affect the lung? Well, more fluid would kind of blow that cavity up like a balloon in your chest. It's inside the ribs. So the cavity can't push outwards. So the only way it can push is it, if it gets more fluid in it is it can push inwards towards the lung. And the lung is a really flexible tissue, it inflates and deflates all the time. So if you get too much fluid in here, it might just squeeze the lung down. And now you're gonna have a much bigger cavity that takes up this space where the lungs used to be. So a bigger cavity means a smaller lung, smaller lung, it's gonna be harder to breathe. So for this, in just short sort of shorthand, what I would write is that uh um more fluid equals larger cavity, larger cavity equals less space, her lungs. And that means it harder to breathe. All right, the real important thing to take away here though, remember the layers of that serous membrane and remember that the cavity is between those layers. The lung is not in the cavity, the cavity surrounds the lung. What's in the cavity is the serous fluid? Was that we'll see you in the next video.
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Problem
Problem
During an organ transplant some serous membrane is transplanted along with the organ. Based on the anatomy of serous membranes, which part of the serous membrane would likely be transplanted along with the organ?
A
Both the parietal and visceral serosa.
B
The parietal serosa.
C
The visceral serosa.
D
Whether the visceral or parietal membrane is transferred would depend on the specific organ.
6
Problem
Problem
The disease pericarditis refers to inflammation of the serous membrane around the heart and can cause intensely sharp chest pain. How does the function of the serous membranes relate to the symptoms of chest pain from pericarditis?
A
Serous membranes like the pericardium have many nerve endings to provide feedback relating to organ function.
B
Despite the lubricating properties of serous fluid, the constant movement of the heart may irritate the already inflamed tissue.
C
Pain from inflamed tissue indicates a likely viral or bacterial infection. A major function of the serous membranes is to prevent bacteria and viruses from reaching vital organs.
D
Inflammation of the visceral side of the serous membrane may reduce the rate of diffusion of vital nutrients and ions from the serous fluid into the cardiac muscle.
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