The protective membrane around the lungs is called the pleura

The protective membrane around the lungs is called the pleura. The pleura consists of two layers: the visceral pleura, which covers the outer surface of the lungs, and the parietal pleura, which lines the inside of the chest cavity.

These two layers are separated by a small amount of pleural fluid, which helps reduce friction and allows the lungs to expand and contract smoothly during breathing.