Which term denotes the membrane enclosing the lungs?

• A. Pleura
• B. Alveoli
• C. Bronchi
• D. Pharynx

Answer: (A)

The pleura is the membrane surrounding the lungs. It consists of two layers: the visceral pleura that covers the lungs themselves and the parietal pleura that lines the chest wall and diaphragmatic surface. Between these layers is the pleural cavity, which contains a small amount of lubricating fluid to reduce friction as you breathe, allowing smooth expansion and recoil of the lungs. This makes the pleura the specific structure that encases the lungs. In contrast, alveoli are the tiny air sacs where gas exchange occurs; bronchi are the main airways that conduct air into the lungs; and the pharynx is the throat region that connects the nasal and oral cavities to the larynx and esophagus.