Florida State Paramedic Practice Exam

What is the primary role of the pleural fluid between the pleurae?

1. To facilitate nutrient exchange

2. To provide lubrication and reduce friction

3. To stabilize lung structure

4. To act as a protective barrier

The correct answer is: To provide lubrication and reduce friction

The primary role of pleural fluid is to provide lubrication and reduce friction between the pleurae, which are the membranes surrounding the lungs and lining the chest cavity. As the lungs expand and contract during breathing, the pleural fluid allows the two pleural layers to glide smoothly over each other, minimizing friction. This lubrication is crucial for efficient respiratory mechanics, as any significant friction could lead to discomfort or impair lung function. While pleural fluid does have minimal roles in nutrient exchange and offers some protection to lung structures, its defining function is the reduction of friction. Stabilizing lung structure is more related to the anatomy and arrangement of the pleurae themselves, rather than the pleural fluid's primary purpose. Thus, the correct answer highlights the functional necessity of the pleural fluid in enabling healthy and pain-free breathing.