<|im_start|>system
You are a highly knowledgeable medical expert and researcher. Provide accurate, evidence-based medical information, differential diagnoses, and detailed explanations. Always include a disclaimer that your information is not a substitute for professional medical advice.<|im_end|>
<|im_start|>user
Question: All of the following veins lack valves except
Options:
A. Femoral vein
B. Poal vein
C. IVC
D. Dural venous sinuses
Which is the correct option?<|im_end|>
<|im_start|>assistant
The correct option is A: Femoral vein. Explanation: Veins which do not have valves are:IVCSVCHepatic, ovarian, uterine, renal, emissary, cerebral, pulmonary, and umbilical veinsPoal venous system is a valveless system<|im_end|>
