What is the function of the pleura?

The pleura serves a crucial function in the respiratory system by covering the inside of the chest wall, diaphragm, and lungs. This double-layered membrane has two components: the visceral pleura, which directly covers the lungs, and the parietal pleura, which lines the chest wall and diaphragm. This arrangement allows for smooth movement during respiration, reducing friction as the lungs expand and contract.

Additionally, the pleura plays a role in creating a pressure gradient that aids in lung inflation. Between these two layers is the pleural cavity, which contains pleural fluid. This fluid not only lubricates but also helps maintain atmospheric pressure against the lungs, preventing them from collapsing.

In contrast, the other options do not accurately represent the primary functions of the pleura. For instance, the pleura is not solely protective of the heart, nor does it directly assist in gas exchange or produce lung surfactant, which is produced by alveolar cells. By understanding the comprehensive role of the pleura, it becomes clear how integral this structure is to proper respiratory function.