Type I Alveolar Cells, also known as type I pneumocytes, are thin, flat cells that line the alveoli, the tiny air sacs in the lungs. They cover about 95% of the alveolar surface area and play a crucial role in gas exchange, allowing oxygen to enter the blood and carbon dioxide to exit. Their thin structure facilitates this process, making them essential for efficient respiration. In addition to their role in gas exchange, Type I Alveolar Cells also help maintain the integrity of the alveolar barrier. They are supported by Type II Alveolar Cells, which produce surfactant, a substance that reduces surface tension in the alveoli, preventing collapse during exhalation. Together, these cells ensure proper lung function and respiratory health.