The pleural membrane surrounds which structure in the body?

The pleural membrane is a double-layered serous membrane that specifically surrounds the lungs. It consists of two portions: the visceral pleura, which closely adheres to the lung surface, and the parietal pleura, which lines the chest wall. This anatomical design plays a crucial role in respiration by creating a pleural cavity filled with pleural fluid, which reduces friction between the lung surfaces and the chest wall during breathing. This fluid allows the lungs to expand and contract efficiently. Moreover, the pleural membrane aids in maintaining negative pressure within the pleural cavity, which is essential for lung inflation.

In contrast, the heart is surrounded by the pericardium, the liver is contained within the peritoneal cavity and is not directly surrounded by a membrane like the pleura, and the kidneys are also encapsulated by a renal capsule but do not have a pleural membrane. Understanding the specific function and structure of the pleural membrane is key for recognizing its importance in respiratory physiology.