Type I Pneumocytes are specialized cells that line the alveoli, the tiny air sacs in the lungs where gas exchange occurs. They are thin and flat, allowing for efficient diffusion of oxygen and carbon dioxide between the air in the alveoli and the blood in the surrounding capillaries. These cells cover about 95% of the alveolar surface area. In addition to facilitating gas exchange, Type I Pneumocytes play a role in maintaining the structure of the alveoli. They are supported by Type II Pneumocytes, which produce surfactant, a substance that reduces surface tension and prevents the alveoli from collapsing. Together, these cells are essential for proper lung function.