AP BIOLOGY

Detailed explanation-1: -The main functions of surfactant are as follows: (1) lowering surface tension at the air–liquid interface and thus preventing alveolar collapse at end-expiration, (2) interacting with and subsequent killing of pathogens or preventing their dissemination, and (3) modulating immune responses.

Detailed explanation-2: -The surfactant reduces the surface tension of water by adsorbing at the liquid–gas interface. They also reduce the interfacial tension between oil and water by adsorbing at the liquid–liquid interface.

Detailed explanation-3: -What is Surfactant? A surfactant, at its most basic, is a substance that is designed to reduce the surface tension of a liquid. For many operations in manufacturing processes, it is necessary for a liquid to spread out and wet a surface.

Detailed explanation-4: -In the presence of surfactant, surface tension is increased at high lung volume and decreased at low lung volume. The result is that the lungs can maintain alveoli at many different volumes. Otherwise, the gas in small alveoli would empty into large alveoli.