This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'White infract is not seen in which of the following \nSelect and explain. \nA. Liver, B. Kidney, C. Spleen, D. Hea', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ref Robbins 8/e p128; 7/e p138 see explanations of earlier question White infarcts occur with aerial occlusions in solid organs with end-aerial circulations (e.g., hea, spleen, and kidney), and where tissue density limits the seepage of blood from adjoining patent vascular beds (Fig. 3-17, B). Infarcts tend to be wedge-shaped, with the occluded vessel at the apex and the organ periphery forming the base (Fig. 3-17); when the base is a serosal surface, there is often an overlying fibrinous exudate. Lateral margins may be irregular, reflecting flow from adjacent vessels. The margins of acute infarcts typically are indistinct and slightly hemorrhagic; with time, the edges become better defined by a narrow rim of hyperemia attributable to inflammation. Infarcts resulting from aerial occlusions in organs without a dual circulation typically become progressively paler and sharply defined with time (Fig. 3-17, B). By comparison, hemorrhagic infarcts are the rule in the lung and other spongy organs (Fig. 3-17, A). Extravasated red cells in hemorrhagic infarcts are phagocytosed by macrophages, and the heme iron is conveed to intracellular hemosiderin.', 'role': 'assistant'}]