What role does the pleura play in the respiratory system?

The pleura is a vital component of the respiratory system, serving the primary role of protecting and lubricating the lungs. It consists of two layers: the visceral pleura, which adheres directly to the lung surface, and the parietal pleura, which lines the chest wall.

Between these layers is the pleural cavity, which contains pleural fluid. This fluid plays an essential role by reducing friction during breathing movements, allowing the lungs to expand and contract smoothly within the thoracic cavity. Additionally, the pleura helps to maintain intrapleural pressure, which is crucial for lung inflation. By ensuring the lungs can move freely and remain properly positioned within the rib cage, the pleura aids in effective ventilation and overall respiratory function.

While other options touch on important aspects of the respiratory system, they do not accurately represent the specific function of the pleura. For instance, controlling airflow primarily involves the bronchial passageways and the diaphragm, while gas exchange is a function of the alveoli within the lungs. Blood flow regulation relates more to the cardiovascular system and is not a direct role of the pleura. Thus, the correct choice highlights the protective and lubricating functions critical to respiratory health.