Final answer:
The lungs are enclosed in pleural membranes, composed of the visceral and parietal pleurae, which reduce friction in the pleural cavity.
Step-by-step explanation:
The lungs are enclosed in pleural membranes. The pleura of the lungs encloses each lung within a cavity and consists of two layers: The visceral pleura, which is superficial to the lungs, and the parietal pleura, which is the outer layer that connects to the thoracic wall, mediastinum, and diaphragm. The space between these layers is known as the pleural cavity, which contains a small amount of fluid to reduce friction as the lungs expand and contract.