This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Heart, Circulation, and Blood, Subject name: Physiology
Systolic BP is directly proportional to: 
Select and explain. 
A. Compliance of vessel wall, B. Stroke volume, C. Radius of vessel, D. Elasticity.
B: Stroke volume
Answer: B: Stroke volume 
Explanation: Ans: b (Stroke volume.) Ref: Ganong, 22nd ed, p. 590Arterial pressure is the product of cardiac output and peripheral resistance. But remember cardiac output = stroke volume toeart rate.i.e., BP = stroke volume toeart rateperipheral resistance.BP a stroke volume.Systolic BP (SBP) = Is the highest pressure during cardiac cycle, occurs in systole.It depends on:Stroke volume (SV) - As SV increases, SBP increases.Compliance of vessel - As compliance decreases, SBP increases (windkessel effect, e.g.. old age)Diastolic BP (DBP) =is the lowest pressure during cardiac cycle: occurs during diastole.It depends on:Peripheral resistance- As PR increases, DBP increasesMean Arterial Pressure (MAP) =average pressure during cardiac cycle.MAP=SBP+ 3 23DBP(or)MAP= DBP + 1/3 PPPP=SBP-DBPSome important values from respiratory system