Question

Describe LaPlace's Law and apply it to the alveolar fluid lining.

A) LaPlace's Law states that the pressure inside a spherical structure is directly proportional to the surface tension and inversely proportional to the radius of the sphere. In the context of the alveoli, smaller alveoli have higher pressure, which can lead to airway collapse.
B) LaPlace's Law is not relevant to alveolar fluid lining.
C) LaPlace's Law is a law of fluid dynamics that governs the flow of blood in the circulatory system and does not apply to the alveolar fluid lining.
D) LaPlace's Law states that the pressure inside a spherical structure is inversely proportional to the surface tension and directly proportional to the radius of the sphere. Smaller alveoli have lower pressure, which aids in alveolar expansion.

Answer 1

LaPlace's Law relates to the alveoli in that it describes how pressure inside an alveolus is affected by surface tension and radius. Smaller alveoli would have higher pressures; however, pulmonary surfactant prevents their collapse. This surfactant modulates surface tension, contributing to effective gas exchange and lung function.

Step-by-step explanation:

LaPlace's Law is pertinent when discussing the physiology of the lungs, especially the function of the alveoli. It states that the pressure inside a spherical structure like an alveolus is directly proportional to the surface tension of the fluid lining the alveolus and inversely proportional to the radius of the alveolus. Mathematically, we can express LaPlace's Law as P = 2T/r, where P represents the pressure, T is the surface tension, and r is the radius of the sphere.

Applying this to the alveolar fluid lining, we see that smaller alveoli would naturally have higher pressures than larger ones due to their smaller radius. In the lungs, the presence of a pulmonary surfactant reduces the surface tension in smaller alveoli, thus preventing collapse, and ensuring even distribution of air amongst all alveoli irrespective of their size. This unique capacity to modulate surface tension helps maintain proper lung function during both inhalation and exhalation.

Moreover, lung compliance and ability to stretch, alongside the reduction in surface tension provided by the surfactant, contribute to lower air pressures within larger lung volumes, facilitating gas exchange.