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': 'Which of the following pigments are involved in free \nSelect and explain. \nA. Lipofuscin, B. Melanin, C. Bilirubin, D. Hematin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ref Robbins 7/e p39; 9/e p64 Impoant points about lipochrome or lipofuscin Lipofuscin, or "wear-and-tear pigment," is an insoluble brownish-yellow granular intracellular material that accumulates in a variety of tissues (paicularly the hea, liver, and brain) as a function of age or atrophy. Lipofuscin represents complexes of lipid and protein that derive from the free radical-catalyzed peroxidation of polyunsaturated lipids of subcellular membranes. It is not injurious to the cell but is a marker of past free radical injury. The brown pigment (Fig. 1-27), when present in large amounts, impas an appearance to the tissue that is called brown atrophy. By electron micros- copy, the pigment appears as perinuclear electron-dense granules', 'role': 'assistant'}]