pleura

(PLOOR-uh) A thin layer of tissue that covers the lungs and lines the interior wall of the chest cavity. It protects and cushions the lungs. This tissue secretes a small amount of fluid that acts as a lubricant, allowing the lungs to move smoothly in the chest cavity while breathing.

(PLOO-ruh): The thin lining that covers the lungs and the inside of the chest wall that cushions the lungs. The pleura normally releases a small amount of fluid. The fluid helps the lungs move freely during breathing.