What is the primary role of surfactant in the alveoli?

Surfactant plays a vital role in the alveoli by reducing surface tension. The alveoli are tiny air sacs in the lungs where gas exchange occurs, and they are lined with a thin layer of fluid. This fluid creates high surface tension, which could cause the alveoli to collapse, especially during the process of exhalation. Surfactant, primarily composed of lipids and proteins, works to lower this surface tension, allowing the alveoli to remain open and preventing them from collapsing. By doing so, surfactant not only improves lung compliance but also facilitates easier inflation of the lungs during breathing. This reduction in surface tension is critical for maintaining the structural integrity of the alveoli and ensuring efficient gas exchange.