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: Physiology
[{'content': 'Anticoagulant produced by mast cells - \nSelect and explain. \nA. Antithrombin III, B. Protein C, C. Protein C, D. Heparin', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Heparin Mast cells Mast cells are bone marrow derived cells. They are found predominantly near blood vessels and nerves and in subepithelial sites, where local immediate hypersensitivity reaction tend to occur. Mast cells have cytoplasmic membrane-bound granules that contain a variety of biologically active mediators. These granules are referred as metachromatic granules. Mast cells are central to the development of immediate hypersensitivity.", 'role': 'assistant'}]