MEDICAL PHYSIOLOGY

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: -When a surfactant is introduced into a liquid, their molecules migrate to the surface, which creates a layer of weakly attracted molecules, leading to a decrease in the surface tension. Once the air–liquid interface is saturated with surfactant, the molecules accumulate in the bulk of the solution and form micelles.

Detailed explanation-3: -Surfactant reduces the surface tension of water, keeping the alveoli open so that we can breathe easily.

Detailed explanation-4: -Pulmonary surfactant reduces the surface tension at the air-liquid interface throughout the lung by forming a lining layer between the aqueous airway liquid and the inspired air.

Detailed explanation-5: -A surfactant is a substance that reduces the surface tension of a liquid. For instance, a small puddle of water on a desk has high surface tension. But adding a surfactant such as dish soap to the puddle would reduce its surface tension and cause the water to spread out more.