Organization of the Body: Serous Membrane Locations - Online Tutor, Practice Problems & Exam Prep

Serous membranes, including the pleurae, pericardium, and peritoneum, surround vital organs in the thoracic and abdominal cavities. The pleurae encompass the lungs, the pericardium encases the heart, and the peritoneum envelops most digestive organs. Understanding these membranes is crucial for grasping organ movement and function. The visceral layers touch the organs, while the parietal layers line the cavity walls, highlighting the complex interactions within the body. This knowledge is foundational for studying anatomy and physiology, particularly in relation to organ systems and their protective structures.

Locations of Serous Membranes

We've been talking about serous membranes and serous cavities in general, and we've been using the heart as an example when we do that. But of course, the heart is not the only organ that moves inside of your body. When you breathe, your lungs expand and contract. As food moves through the digestive tract, those organs change shape. As you move your body, the organs inside you need to move with you. So most of those organs are going to be surrounded by serous membranes and serous cavities much like the heart is. We're now going to name the specific serous membranes of the body and say where they're located. So we're going to start by just noting that there are 4 serous membranes and they are located in the thoracic and abdominal pelvic cavities.

The first two are going to be the pleurae. The pleurae form the pleural cavities, and these surround each lung. Now, remember, the lung is not in the cavity. The cavity surrounds the lung. We can take a look at our anatomical model over here, and we see a model from a sagittal view, and we can see the anterior body cavity. And here in blue, and taking up most of the thoracic cavity here, we see pretty much the shape of a lung, and it's labeled pleura. One pleura surrounds one lung. Now you may notice that the pleura here ends in a single "a" and over here it's pleurae, where it ends in "ae." These are these kind of weird Latin endings where a single "a" means singular. One pleura surrounds one lung, and "ae," pleurae, is multiple. There are 2 pleurae that surround the lungs. That sometimes gets me a little confused, but I can use it to help me remember that the pleurae and pleural cavities refer to the lungs. And that's because 'pleural cavities' is plural. There's more than one lung. There's more than one pleural cavity. Now those two words, plural and pleural, they come from completely different roots, but for these purposes, it doesn't matter. 'Plural' means more than 1. You have more than one lung.

Pericardium is next, and the pericardium forms the pericardial cavity. This is the membrane and the cavity that surrounds the heart. And again, as we look over at our anatomical model here, we can see the shape of a heart in green at the anterior portion of the thoracic cavity here, and it's labeled pericardium as that's the membrane surrounding the heart. Now remember this, 'cardiac' means heart and 'peri' means around. So when you put those together, pericardium, it literally means 'around the heart,' and this is the membrane and the cavity that surrounds the heart.

Our final membrane and cavity, well, the membrane is the peritoneum, and that's going to form the peritoneal cavity. This is going to surround most digestive organs. And again, as we look over at our anatomical model, we can see the peritoneum here in this sort of yellow or orange color, and it's taking up most of the abdominal cavity and it even enters down into the pelvic cavity some. And that's because, remember, there is no hard dividing line between the pelvic cavity and the abdominal cavity, and it's going to be labeled peritoneum. So the peritoneum is going to be a little different than these other cavities because these other cavities all surrounded one organ. The peritoneum is surrounding most digestive organs. You have several digestive organs and some of them are kind of crazy shapes. Right? Your intestines are over 20 feet long, and all of that intestine is going to be touching peritoneum and not other organs. So the shape of this membrane and the shape of this cavity is going to be really complex. It's going to be really big and much more complex than the other membranes. And you can remember that a little bit because peritoneum literally means 'stretched around.' It's going to be stretched around a whole bunch of different organs. We're

Organization of the Body: Serous Membrane Locations Example 1

This example asks us to match each layer of the serous membrane with an organ or structure it touches. So let's see what we have to match. We have the visceral pericardium, the parietal pleura, the visceral peritoneum, and the parietal peritoneum. Alright. Before I get going here, I just want to note that for me all those 'p' words start getting jumbled in my head. Right? We have pericardium, parietal peritoneum. So let's just take it step by step and break down each word one by one. So first off, we have A, the visceral pericardium. So visceral, remember, viscera refers to the organ. So, this is the organ side of the membrane and 'pericardium'. Well, we said 'peri' means around and 'cardiac' is heart, so it's around the heart, on the organ side of the heart. So it's going to be touching the heart. There it is, A. The first option, heart.

Next up, we have parietal pleura. Now remember, parietal meant wall, so it's going to be touching the body wall and 'pleura'. Right? Remember, like, pleura and pleural cavities. That's plural. There's more than one pleura because there are two lungs. So touching the body wall around the lungs is going to be touching the walls of the thoracic cavity or the chest. So there we have it, B down here, the wall of the chest.

Next up, we have the visceral peritoneum. Visceral, remember, 'visceral' again is the viscera. That's going to be the organ side of the membrane. And 'peritoneum'. 'Peritoneum', we said stretched around, and it's stretched around all these different digestive organs. So, the visceral peritoneum is going to be touching the organs in the abdomen. We have an organ of the abdomen over here in the liver. So I feel confident that the visceral peritoneum is going to be touching the liver.

Then finally, we have the parietal peritoneum. Now we only have one more place, but let's break it down anyway. Parietal meant wall, and peritoneum was the membrane that's in the abdominal and a little bit into the pelvic cavities. So if it's touching the body wall in the abdominal cavity, it's going to be touching the wall of the abdomen. There it is, D, wall of the abdomen.

Okay. Again, those words can be a little confusing. Take them step by step, break them down in your head, and you'll do fine. See you in the next video.

Which body cavity has multiple serous cavities within it?

• A. Thoracic
• B. Abdominopelvic
• C. Pleural
• D. Every body cavity contains one serous cavity.

Here’s what students ask on this topic:

What are the main serous membranes in the human body and their locations?

The main serous membranes in the human body are the pleurae, pericardium, and peritoneum. The pleurae are located in the thoracic cavity and surround the lungs. Each lung is encased in its own pleural cavity. The pericardium is also in the thoracic cavity and surrounds the heart, forming the pericardial cavity. The peritoneum is found in the abdominal and pelvic cavities, enveloping most of the digestive organs. These membranes play a crucial role in reducing friction between moving organs and their surrounding structures.

What is the difference between visceral and parietal layers of serous membranes?

The visceral and parietal layers of serous membranes serve different functions. The visceral layer directly covers and adheres to the organs (viscera), providing a smooth, frictionless surface. For example, the visceral pericardium covers the heart, the visceral pleura covers the lungs, and the visceral peritoneum covers the digestive organs. The parietal layer, on the other hand, lines the cavity walls. The parietal pericardium lines the pericardial cavity, the parietal pleura lines the thoracic cavity, and the parietal peritoneum lines the abdominal cavity. These layers create a fluid-filled space that reduces friction during organ movement.

How do the pleurae function in the respiratory system?

The pleurae are essential for the proper functioning of the respiratory system. They consist of two layers: the visceral pleura, which covers the lungs, and the parietal pleura, which lines the thoracic cavity. Between these layers is the pleural cavity, filled with pleural fluid. This fluid reduces friction between the lungs and the chest wall during breathing. The pleurae also help maintain negative pressure within the pleural cavity, which is crucial for lung expansion during inhalation. Any disruption in this system, such as a pneumothorax, can impair breathing.

What role does the pericardium play in protecting the heart?

The pericardium is a double-layered serous membrane that encases the heart, forming the pericardial cavity. It consists of the visceral pericardium (inner layer) and the parietal pericardium (outer layer). The pericardial cavity between these layers contains pericardial fluid, which reduces friction as the heart beats. The pericardium also provides a protective barrier against infections and physical shocks, and it helps anchor the heart within the thoracic cavity, preventing excessive movement. This structural support is vital for maintaining the heart's position and function.

Why is the peritoneum considered more complex than other serous membranes?

The peritoneum is considered more complex than other serous membranes because it surrounds multiple digestive organs, each with unique shapes and sizes. Unlike the pleurae and pericardium, which each encase a single organ (lungs and heart, respectively), the peritoneum envelops organs like the stomach, intestines, liver, and more. This complexity is due to the extensive surface area and the intricate arrangement required to cover these organs. The peritoneum also forms various folds and extensions, such as the mesentery, which supports and supplies blood to the intestines, adding to its complexity.