This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
In poal venous system, valves are present at 
Select and explain. 
A. The junction of superior mesentric aery with the splenic aery, B. Within the poal vein only, C. In the intrahepatic poion of poal vein, D. The whole system is valveless
D: The whole system is valveless
Answer: D: The whole system is valveless 
Explanation: D i.e. The whole system is valvelessLike vena Cava, the poal vein and its tributaries are without valvesQ. The normal pressure in poal vein is 3-5 mmHg and the increase in venous pressure is distributed throughout the splanchenic circulation.