What is the smooth thin lining that surrounds the lungs and allows expansion and contraction during breathing?

What is the smooth thin lining that surrounds the lungs and allows expansion and contraction during breathing?

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

Answer: (A)

The lining is the pleura, a two-layer serous membrane that surrounds the lungs. The visceral pleura covers the lungs themselves, while the parietal pleura lines the chest wall and diaphragm. Between these layers is the pleural cavity, filled with a tiny amount of lubricating fluid that lets them slide smoothly against each other as you breathe. This setup allows the lungs to expand and contract in harmony with the chest wall. The other terms refer to parts of the airway or gas-exchange surfaces, not the lining around the lungs.