What is the primary function of surfactant in the lungs?

Surfactant serves a crucial role in lung physiology primarily by reducing surface tension within the alveoli. The alveoli are tiny air sacs where gas exchange occurs, and they are lined with a thin layer of fluid. If surface tension were not effectively reduced, the high surface tension could lead to alveolar collapse, especially during exhalation when the lung volume decreases. By creating a film that lowers this surface tension, surfactant ensures that the alveoli remain open and stable, facilitating effective gas exchange during respiration.

This reduction in surface tension not only supports alveolar stability but also plays a vital role in increasing lung compliance, enabling easier expansion of the lungs during inhalation. Therefore, the primary function of surfactant in the lungs is essential for maintaining alveolar integrity and optimizing respiratory function.