This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
Laplace's law, all except 
Select and explain. 
A. P = T/r, B. P = 2T/r, C. T = Pr/W, D. T = WP/R
D: T = WP/R
Answer: D: T = WP/R 
Explanation: Law of Laplace, an impoant physical principle with several other applications in physiology. This law states that tension in the wall of a cylinder (T) is equal to the product of the transmural pressure (P) and the radius (r) divided by the wall thickness (w):T = Pr/w Ref: Ganong's Review of Medical Physiology 25th Edition. Page: 574