Pleuraõõne

Pleuraõõne, also known as the pleural cavity, is the potential space between the two layers of pleura, the serous membranes that surround the lungs. The visceral pleura covers the surface of the lungs, while the parietal pleura lines the inner surface of the chest wall, the diaphragm, and the mediastinum. Under normal circumstances, the pleural cavity is not an actual space but rather a thin film of pleural fluid that allows the lungs to glide smoothly against the chest wall during respiration. This fluid acts as a lubricant and also helps to create surface tension, which keeps the visceral and parietal pleura in close apposition. The pressure within the pleural cavity, known as intrapleural pressure, is typically negative relative to atmospheric pressure. This negative pressure is crucial for lung expansion. If air enters the pleural cavity, a condition called pneumothorax occurs, causing the lung to collapse. Accumulation of excess fluid in the pleural cavity is called pleural effusion.