The pleural membrane is thin, moist, slippery and has two layers. The outer, or parietal, pleura lines the inside of the rib cage and the diaphragm while the inner, visceral or pulmonary, layer covers the lungs. The pleura.

Membrane covering the lungs:
The membrane covering the lungs is called the pleura. The pleura is a double-layered membrane that surrounds the lungs and lines the chest cavity. It plays a crucial role in protecting and supporting the lungs as they expand and contract during breathing.

Functions of the pleura:
- The pleura helps to reduce friction between the lungs and the chest wall during breathing movements.
- It creates a seal around the lungs, which allows for changes in pressure within the chest cavity during breathing.
- The pleura also helps to maintain the shape and position of the lungs within the chest cavity.

Structure of the pleura:
- The pleura consists of two layers: the visceral pleura and the parietal pleura. The visceral pleura is the inner layer that directly covers the surface of the lungs, while the parietal pleura lines the chest cavity.
- Between the two layers of the pleura is a thin layer of fluid called pleural fluid. This fluid helps to lubricate the surfaces of the pleura, reducing friction during breathing.

Importance of the pleura:
- The pleura is essential for normal lung function, as it allows for the smooth movement of the lungs within the chest cavity.
- Any disruption to the pleura, such as inflammation or infection, can lead to conditions like pleurisy or pleural effusion, which can cause chest pain and difficulty breathing.
In conclusion, the pleura is a vital membrane covering the lungs that plays a crucial role in protecting and supporting respiratory function.