A pneumocyte is a type of cell found in the lungs, specifically in the alveoli, which are tiny air sacs where gas exchange occurs. There are two main types of pneumocytes: type I and type II. Type I pneumocytes are thin and cover most of the alveolar surface, facilitating the exchange of oxygen and carbon dioxide. Type II pneumocytes are larger and produce surfactant, a substance that reduces surface tension in the alveoli, preventing their collapse during exhalation. Pneumocytes play a crucial role in maintaining lung function and overall respiratory health. When the lungs are damaged or infected, such as in conditions like pneumonia or COVID-19, the function of pneumocytes can be impaired, leading to difficulties in breathing and gas exchange. Understanding the role of pneumocytes is essential for developing treatments for various lung diseases.