UPSC CSE Prelims
Question 36
Which one of the following is synthesised in human body that dilates blood vessels and increases blood flow ?
View correct answer and explanation
Correct answer: A
Correct Option: A (Nitric oxide)
Explanation: Endothelial cells synthesise nitric oxide (NO), a signalling molecule that relaxes vascular smooth muscle and widens blood vessels.
Option-wise Analysis:
A. Correct-nitric oxide is a physiological vasodilator.
B. Incorrect-Nitrous oxide (N₂O) is an anaesthetic gas, not the usual endothelial vasodilator.
C. Incorrect-Nitrogen dioxide (NO₂) is a harmful air pollutant.
D. Incorrect-Dinitrogen pentoxide is a reactive oxide, not a normal vascular signalling molecule.