Question

Which of the following statements about surfactant is false?

a. it's a detergent-like mix of lipids and peptides that decrease surface tension
b. it's part of the aqueous film covering the alveolar surfaces
c. it reduces that amount of work require to inflate the lung
d. it works by increasing the attraction of water molecules to each other

Answer 1

The false statement about surfactant is that it works by increasing the attraction of water molecules to each other. In fact, surfactant decreases the surface tension in the lungs, making it easier for the alveoli to expand during inhalation and preventing their collapse during exhalation.

Step-by-step explanation:

The question concerns the function of surfactant in the lungs, particularly within the alveoli. Among the statements given, the false one is d. it works by increasing the attraction of water molecules to each other. Surfactant is a complex mixture of phospholipids and proteins that reduces surface tension, rather than increasing it.

Surfactant functions to decrease the surface tension at the air-tissue/water interface of the alveoli, which is crucial for proper lung function. During inhalation, the surfactant molecules spread apart, reducing surface tension and thus the work required to inflate the lung. Conversely, during exhalation, these molecules come closer together again, maintaining low surface tension and preventing alveoli collapse.

This unique behavior ensures that smaller alveoli do not collapse and larger ones do not over-expand. The dynamic nature of surfactant is critical for maintaining the stability and compliance of the lung's air spaces.