Biological Systems MCAT Practice Exam

Which part of the pleura lines the surface of the lungs?

1. Visceral pleura

2. Parietal pleura

3. Costal pleura

4. Diaphragmatic pleura

The correct answer is: Visceral pleura

The visceral pleura is the layer of pleura that directly covers the surface of the lungs. It is a serous membrane that adheres tightly to the lung tissue, following the contours and fissures of the lungs. This anatomical feature is essential for the proper functioning of the respiratory system, as it provides a smooth, frictionless surface that allows the lungs to expand and contract during breathing. The visceral pleura is distinct from the parietal pleura, which lines the thoracic cavity and is further removed from the lung surface; the two layers are continuous with each other at the hilum of the lungs, where structures such as blood vessels and bronchi enter and exit the lungs. The different pleural layers serve specific roles in respiratory mechanics, and understanding their functions is crucial for comprehending how pleural pressure changes facilitate ventilation.