Question

According to Laplace's law, the air pressure necessary to prevent the collapse of an alveolus is directly proportional to the surface tension and inversely proportional to the alveolus's radius. Therefore, as an alveolus gets __________ during __________, there is an increased need for the actions of surfactant to prevent alveolar collapse.

Answer 1

During exhalation, as the alveolus becomes smaller, the need for surfactant increases to maintain stability and prevent collapse, ensuring efficient lung function.

Step-by-step explanation:

According to Laplace's law, as an alveolus gets smaller during exhalation, there is an increased need for the actions of surfactant to prevent alveolar collapse. This is because the tension in the walls of these alveoli is produced by membrane tissue and a liquid that contains surfactants, which are surface-tension reducing substances. The presence of surfactant is critical to maintain balance, as it ensures that during inhalation, despite increased wall tension due to increased radius, and during exhalation, with a decrease in surface tension, the alveoli remain stable. Small alveoli are prevented from collapsing, and large alveoli are restricted from over expanding, which is essential for effective gas exchange in the lungs.