What is the primary function of surfactant in the lungs?

The primary function of surfactant in the lungs is to reduce surface tension in the alveoli, the tiny air sacs where gas exchange occurs. Surfactant is a complex mixture of lipids and proteins that plays a crucial role in maintaining the stability of the alveoli. By reducing surface tension, it prevents the alveoli from collapsing during exhalation, allowing them to remain open and available for gas exchange during the next inhalation.

This reduction of surface tension is vital for normal respiratory function, as it ensures that the alveoli can expand easily during inhalation and helps to prevent atelectasis, which is the complete or partial collapse of the lung. Surfactant allows the alveoli to maintain their structure and enhance lung compliance, making it easier for the lungs to expand and contract effectively.

While surfactant indirectly contributes to enhancing gas exchange and facilitating lung expansion, its most direct and critical role is related to the reduction of surface tension, thereby reducing the work of breathing and improving overall lung function.