Which of the following is NOT a function of surfactants?

Surfactants play a crucial role in maintaining proper lung function, particularly by reducing surface tension in the alveoli, which prevents collapse and facilitates gas exchange. They work by forming a thin layer on the surface of the alveolar liquid, thereby decreasing the surface tension and improving lung compliance.

The option stating that surfactants increase blood viscosity is not accurate in the context of surfactant function. Surfactants primarily affect the pulmonary system, focusing on improving breathing mechanics rather than influencing blood properties, like viscosity. Therefore, indicating that surfactants increase blood viscosity is inconsistent with their biological function.

The other options correctly describe the roles of surfactants: they facilitate gas exchange by maintaining stability and preventing alveolar collapse, and they reduce surface tension, allowing the lungs to inflate easily.