What membrane encases the lungs?

The correct answer is the pleura cavity. The pleura is a double-layered serous membrane that surrounds each lung and lines the chest cavity. It consists of two layers: the visceral pleura, which is attached directly to the lung surface, and the parietal pleura, which lines the inner chest wall.

This membrane serves several important functions. It creates a lubricated surface that allows the lungs to expand and contract freely during breathing. The space between these two layers, known as the pleural cavity, contains a small amount of pleural fluid that further reduces friction. This mechanism plays a crucial role in facilitating respiration and ensuring that the lungs can function effectively without the impediments of friction from surrounding tissues.

The other options refer to different membranes with specific functions in different body systems; for instance, the pericardium encases the heart, the peritoneum lines the abdominal cavity, and the synovial membrane is found in joints. These structures serve distinct purposes and are not involved in the respiratory function of encasing the lungs as the pleura does.