This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bronchopulmonary Segments, Embryonic veins, Subject name: Anatomy
Pulmonary veins develop from: 
Select and explain. 
A. Sixth aoic arch, B. Primitive left atrium, C. Left common cardinal vein, D. Left vitelline vein
B: Primitive left atrium
Answer: B: Primitive left atrium 
Explanation: According to some authorities, pulmonary veins develop from the left atrial wall. There is no consensus about whether the pulmonary vein arise as a branch from the left atrium and obtains a connection to the lung plexus OR the pulmonary vein forms as a solitary vessel in the dorsal mesocardium =give rise to 4 pulmonary veins = secondarily get absorbed into wall of left atrium Fig. : Absorption of pulmonary veins into the left atrium. RPV = right pulmonary vein; LPV = left pulmonary vein.