The pleural cavities enclose which structure?

The pleural cavities enclose which structure?

• A. The heart
• B. A lung
• C. The stomach
• D. The liver

Answer: (B)

Each pleural cavity surrounds one lung, forming a double-layered sac with the lung on the inside and the chest wall on the outside. The space between the visceral pleura (on the lung) and the parietal pleura (lining the thoracic cavity) holds a small amount of pleural fluid to reduce friction during breathing. The heart sits in the mediastinum within the pericardial sac, not inside the pleural spaces, and the stomach and liver lie in the abdominal cavity below the diaphragm. So, the structure enclosed by the pleural cavities is the lung.

Each pleural cavity surrounds one lung, forming a double-layered sac with the lung on the inside and the chest wall on the outside. The space between the visceral pleura (on the lung) and the parietal pleura (lining the thoracic cavity) holds a small amount of pleural fluid to reduce friction during breathing. The heart sits in the mediastinum within the pericardial sac, not inside the pleural spaces, and the stomach and liver lie in the abdominal cavity below the diaphragm. So, the structure enclosed by the pleural cavities is the lung.