How do surfactants function in the lungs?

Surfactants play a crucial role in the lungs by decreasing surface tension at the air-liquid interface within the alveoli, which are the tiny air sacs responsible for gas exchange. This reduction in surface tension is vital because it prevents the alveoli from collapsing, especially during exhalation when lung volumes decrease. By reducing the force required to inflate the alveoli, surfactants decrease the work of breathing, making it easier for a person to breathe, particularly in conditions like respiratory distress syndrome.

In addition to their role in reducing surface tension, surfactants help maintain stabilizing balances among the different sizes of alveoli. This keeps them open and functioning properly, which is critical for effective gas exchange. The effects of surfactants lead to improved lung compliance and contribute to efficient respiratory mechanics, ultimately enhancing oxygen delivery to the blood.

Other options, such as increasing airway resistance, promoting inflammation, or enhancing mucus production, do not accurately describe the function of surfactants in the lungs. Instead, surfactants are primarily known for their protective and mechanical roles in maintaining lung integrity and facilitating normal respiratory function.