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
The most impoant source of histamine 
Select and explain. 
A. Mast cells, B. Eosinophil, C. Neutrophils, D. Macrophages
A: Mast cells
Answer: A: Mast cells 
Explanation: ref Robbins 8/e p57,9/e p83 Histamine is synthesized in all tissues, but is paicularly abundant in skin, lung and gastrointestinal tract. Mast cells, which are present in many tissues, are a prominentsource of histamine, but histamine is also secreted by a number of other immune cells.