What is the name of the membrane that is closest to the lungs?

The membrane that is closest to the lungs is the visceral pleura. This double-layered membrane serves a crucial function in the respiratory system. The visceral pleura covers the surface of the lungs, providing a protective barrier while allowing for movement during respiration. As the lungs expand and contract during inhalation and exhalation, the visceral pleura facilitates smooth movement against the surrounding structures.

In contrast, the parietal pleura is the membrane that lines the thoracic cavity itself, providing support and separation from the surrounding chest wall. The pericardium refers to the membrane surrounding the heart, which is distinctly different from the pleural membranes associated with the lungs. The pleural cavity is the space between the parietal and visceral pleura, containing pleural fluid, which reduces friction but is not a membrane itself. The distinction between these terms is essential for understanding their roles in the anatomy of the thoracic cavity.