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
In circulatory system, the highest velocity of blood flow is in the 
Select and explain. 
A. image_question, B. image_question, C. image_question, D. image_question
A: image_question
Answer: A: image_question 
Explanation: In circulatory system, the highest velocity of blood flow is in the aoa. The velocity of blood flow is inversely propoional to vascular cross-sectional area. v=Velocity F= Blood flow through the area A= Vascular cross sectional area Aoa has the least cross sectional area (4.5 cm2) and capillaries have the maximum cross sectional area (4500 cm2). Thus, under resting conditions, the velocity is highest in aoa and least in capillaries. Ref: Guyton and Hall 13th edition Pgno: 169-170