What structure covers the Alveoli and allows the exchange of gases?

The alveoli are covered by a thin layer of epithelial cells and are surrounded by a network of capillaries. This structure, known as the alveolar-capillary membrane, facilitates the exchange of gases (oxygen and carbon dioxide) between the air in the alveoli and the blood in the capillaries. The thinness of this membrane is crucial for efficient gas diffusion.