What is the main function of lung surfactant?

The main function of lung surfactant is to reduce surface tension in the alveoli. Surfactant is a complex mixture of lipids and proteins secreted by the epithelial cells of the alveoli. It plays a crucial role in maintaining the stability and function of the lungs by lowering the surface tension at the air-liquid interface in the alveoli. This reduction in surface tension is essential because it prevents the alveoli from collapsing during exhalation and allows them to expand more easily during inhalation, thus facilitating efficient gas exchange.

Additionally, surfactant helps to keep the lungs compliant, ensuring that they can inflate effectively with each breath. This function is vital for maintaining proper respiratory mechanics and optimizing the surface area available for gas exchange, allowing for sufficient oxygen absorption and carbon dioxide removal. Overall, the presence of surfactant significantly enhances respiratory efficiency and lung function.