Which one of the following is synthesised in human body that dilates blood vessels and increases blood flow ?
A
Nitric oxide
Correct answer
B
Nitrous oxide
C
Nitrogen dioxide
D
Nitrogen pentoxide
Explanation
Nitric oxide (NO) is made in the lining of blood vessels by the enzyme nitric oxide synthase. It relaxes the smooth muscle in vessel walls, widening the vessels and increasing blood flow; nitroglycerine relieves angina by releasing it. Nitrous oxide is laughing gas, an anaesthetic, while nitrogen dioxide and nitrogen pentoxide are toxic compounds the body does not make.
Biology & Health