Pleurae

Pleurae are thin double layers of serous membranes that line the chest cavity and enclose the lungs. They form a protective layer between the lungs and other organs in the chest cavity, allowing the lungs to move freely during breathing. Pleurae also help to keep the lungs inflated and prevent the chest cavity from collapsing when the chest muscles and diaphragm relax. They also aid in the efficient exchange of oxygen and carbon dioxide by preventing air from escaping the lungs while allowing the free flow of air in and out. Additionally, pleurae act as a lubricant that reduces friction between the lungs and the chest walls during breathing. This reduces the risk of chest trauma and facilitates breathing.