pleura

The pleura are two thin, smooth layers of tissue that surround the lungs and line the inside of the chest cavity. The outer layer, called the parietal pleura, attaches to the chest wall, while the inner layer, called the visceral pleura, covers the lungs. Between these layers is a small space filled with a lubricating fluid, allowing the lungs to move smoothly during breathing. The pleura help protect the lungs and facilitate their expansion and contraction efficiently. If the pleura become inflamed or fill with fluid, it can cause pain and breathing difficulties.