What does the pleurae encompass?

The pleurae are a set of serous membranes that form a protective covering around the lungs and line the thoracic cavity. Specifically, there are two layers of pleura: the visceral pleura, which is attached directly to the surface of the lungs, and the parietal pleura, which lines the thoracic wall and diaphragm. This anatomical arrangement allows for a frictionless movement of the lungs during breathing and provides a compartmentalized structure that helps to prevent the spread of infection or disease within the thoracic cavity.

The choice that indicates the pleurae encompasses the heart and lungs is accurate because the pleural cavities specifically surround the lungs. The heart, while located in the thoracic cavity, is contained within its own protective sac known as the pericardium and is not enveloped by the pleurae. Thus, the selection that identifies the pleurae as encompassing both the heart and lungs correctly aligns with the anatomical definitions and functional relevance of the pleural membranes.