AACN ECCO Pulmonary Practice Exam

Surfactant plays a crucial role in lung function by significantly reducing surface tension in the alveoli. The alveoli are tiny air sacs where gas exchange occurs, and they are lined with a thin film of liquid. Without surfactant, the surface tension in these small air sacs would be very high, leading to the potential collapse of alveoli, especially during exhalation when the air volume decreases. By lowering the surface tension, surfactant helps to keep the alveoli stable and ensures they remain open, allowing for effective gas exchange.

Additionally, the presence of surfactant helps to increase lung compliance, making it easier for the lungs to expand and contract during breathing. This function is essential for maintaining proper lung mechanics and overall respiratory efficiency. While surfactant contributes indirectly to respiratory health, its primary and most critical role is the reduction of surface tension, enabling the alveoli to function effectively in oxygen and carbon dioxide exchange.