The lungs are parts of the respiratory system. Pleura and pleural cavity are two important parts that are related to the lungs of the respiratory system. Pleura refers to the serous membrane that lines the pleural cavity, and it is attached to the lungs and chest wall, too.
The key difference between pleura and pleural cavity is their structure and location. Pleura is the thin layer of tissue that covers the lungs while pleural cavity is a fluid filled space that surrounds the lungs.
CONTENTS
1. Overview and Key Difference
2. What is Pleura
3. What is Pleural Cavity
4. Similarities – Pleura and Pleural Cavity
5. Pleura vs Pleural Cavity in Tabular Form
6. Summary – Pleura vs Pleural Cavity
7. FAQ: Pleura and Pleural Cavity
What is Pleura?
Pleura is a vital part associated with the lungs and the respiratory tract. There are two pleura. Each pleura consists of a two-layered membrane that covers each lung. The two distinct layers include the visceral pleura and the parietal pleura. The visceral pleura is the thin, slippery membrane covering the surface of the lungs, whereas the parietal pleura is the outer membrane lining the inner chest wall and diaphragm. The space between the membranes is called the pleural cavity.
The functions of the pleura include cushioning the lung and reducing any friction that may develop between the lungs, chest cavity, and rib cage. Furthermore, there are a number of different medical conditions that can affect the function of the pleura, including pleural effusions, collapsed lung, and cancer.
Figure 01: Pleura and Pleural Cavity
What is Pleural Cavity?
The space enclosed by the pleura is known as the pleural cavity. The pleural cavity has a small amount of liquid known as pleural fluid. This fluid provides lubrication as the lungs expand and contract during respiration. When this fluid accumulates in the pleural cavity, it is referred to as a pleural effusion, and this condition can severely restrict breathing.
The function of the pleural cavity involves cushioning the expansion and contraction of the lungs. It does this smoothly with the aid of the lubricating fluid. Furthermore, disorders that may affect the pleural space are pneumothorax, hemothorax, chylothorax, and mesothelioma.
Similarities Between Pleura and Pleural Cavity
- Pleura and pleural cavity are two important parts that are related to the lungs of the respiratory system.
- Pleura lines the pleural cavity.
- Both these protect the lungs and facilitate respiratory function.
- There are a number of diseases affecting the function of both of these parts.
Difference Between Pleura and Pleural Cavity
Definition
- Pleura is a membrane that lines the thoracic cavity and covers the lungs.
- Pleural cavity is the space between pleura.
Anatomy
- There are two pleurae, one for each lung, and each pleura is comprised of two distinct layers: visceral pleura and parietal pleura.
- The pleural cavity is located between the parietal pleura, which is attached to the chest wall, and the visceral pleura, which is attached to the lungs. It also contains between 15 and 20 ccs of fluid.
Function
- Pleura involves cushioning the lung and reducing any friction that may develop between the lungs, chest cavity, and rib cage.
- Pleural cavity involves cushioning the expansion and contraction of the lungs smoothly with the aid of the lubricating fluid.
Diseases Affecting
- Pleural effusions, a collapsed lung, and cancer can affect the pleura.
- Pleural effusions, pneumothorax, hemothorax, chylothorax, and mesothelioma can affect the pleural cavity.
The following table summarizes the difference between pleura and pleural cavity.
Summary – Pleura vs Pleural Cavity
Pleura is a serous membrane. It folds back on itself to form a two-layered membranous pleural sac. The outer layer is the parietal pleura that attaches to the chest wall. The inner layer is the visceral pleura which covers the lungs, blood vessels, nerves, and bronchi. The pleural cavity is a space between the visceral and parietal pleura. This space contains a tiny amount of serous fluid. This is the basic difference between pleura and pleural cavity.
FAQ: Pleura and Pleural Cavity
1. Is the pleura an organ?
- No, pleura is only considered as a membrane, in contrast to the skin, which is recognized as the largest organ in the body. The pleura lines the thoracic cavity and covers the lungs.
2. What is one of the key functions of the pleura?
- The function of the pleura is allowing optimal expansion and contraction of the lungs during breathing. It also reduces any friction that may develop between the lungs, rib cage, and chest cavity.
3. What causes pleura effusion in lungs?
- Pleural effusion occurs when excess fluid builds up in the area between the lung and the chest wall. It may happen due to many different reasons, including pneumonia or complications from heart, liver, kidney disease, or side effects from cancer.
4. How much pleural fluid is normal?
- In a healthy human, the pleural space normally contains a small amount of fluid, which is about 10 to 20 mL in volume. It also has a low protein concentration that is less than 1.5 g/dL.
5. How does one remove excess fluid from the pleural cavity?
- Thoracentesis is a procedure that helps to remove fluid or air from around the lungs. In this procedure, a needle is put through the chest wall into the pleural space in order to remove the fluid.
Reference:
1. Lynne Eldridge, MD. “What Is the Pleura and Pleural Effusion?” Verywell Health.
2. Mahabadi, Navid. “Anatomy, Thorax, Lung Pleura, and Mediastinum.” StatPearls, U.S. National Library of Medicine.
Image Courtesy:
1. “2313 The Lung Pleurea” By OpenStax College – Anatomy & Physiology, Connexions Web site, Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia
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