What is the function of pleural sac thing that surrounds your lungs?

The pleura is a serous membrane that lines the thoracic cavity and covers the lungs. It consists of two layers, the visceral pleura and the parietal pleura. The visceral pleura is the layer of pleura that is in direct contact with the lungs, while the parietal pleura is the layer of pleura that lines the thoracic cavity.

The pleural space is the potential space between the visceral pleura and the parietal pleura. It contains a small amount of fluid, which helps to lubricate the pleural surfaces and allow the lungs to expand and contract smoothly during breathing.

The pleura has several important functions, including:

* Protecting the lungs: The pleura provides a physical barrier that helps to protect the lungs from injury.

* Lubricating the pleural surfaces: The fluid in the pleural space helps to reduce friction between the visceral pleura and the parietal pleura, allowing the lungs to expand and contract smoothly.

* Creating negative pressure in the pleural space: The negative pressure in the pleural space helps to keep the lungs inflated and prevents them from collapsing.

* Helping to clear infection: The pleura contains immune cells that help to clear infection from the lungs.

The pleura is an important structure that plays a vital role in respiratory function.