Question

Surfactant helps to keep the alveoli from collapsing by___.

a) Reducing surface tension
b) Increasing surface tension
c) Lubricating the alveolar walls
d) Facilitating gas exchange

Answer 1

Surfactant prevents the collapse of the alveoli by reducing surface tension, facilitating both inhalation and exhalation.

Step-by-step explanation:

Surfactant helps to keep the alveoli from collapsing by reducing surface tension. Surfactant, which is a mixture of phospholipids and lipoproteins, reduces the high surface tension between the alveoli tissue and the air within the alveoli. This is crucial because the tension in the alveolar walls, arising from both the membrane tissue and a layer of liquid which contains surfactant, would otherwise tend to cause the alveoli to collapse during exhalation. During inhalation, this surfactant is stretched, increasing wall tension as alveoli expand, and during exhalation, it helps to lower the surface tension, thus preventing the collapse of the alveoli.