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
Pulse pressure in a paicular vessel is determined chiefly by 
Select and explain. 
A. Distance from hea, B. Frictional characteristics of lumen, C. Distensibility, D. Cross-sectional area
C: Distensibility
Answer: C: Distensibility 
Explanation: In advancing age due to loss in elasticity of blood vessels, stretching decreases which results in increased pressure during systole with normal diastolic blood pressure (systolic hypeension). The blood vessels behave like a rigid tube. It is characterized by high pulse pressure. Pulse pressure is determined by elasticity of vessel wall that varies inversely with total peripheral resistance.