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
[{'content': 'Which of the following statement regarding poal venous system is TRUE? \nSelect and explain. \nA. Valves are present at the junction of superior mesenteric vein and splenic vein, B. Whole system is valveless, C. Valves are present in the intrahepatic system, D. There are about 10-12 valves along the entire course', 'role': 'user'}, {'content': 'Answer: B \nExplanation: In adults, the poal vein and its tributaries have no valves. In fetal life and for a sho postnatal period valves are demonstrable in its tributaries, but they usually atrophy. Rarely some persist in an atrophic form into adulthood. Poal venous system comprises of poal vein and its 3 tributaries, splenic vein, superior and inferior mesenteric vein. Thses veins drain the blood from the intestinal tract, from the oesophagus to the rectum, from the spleen and pancreas to the liver. Poal vein carries 75% of total blood flow to the liver. Normal poal pressure is 5 - 10mmHg.', 'role': 'assistant'}]