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': 'All are present in dense granules of platelets EXCEPT: \nSelect and explain. \nA. ADP, B. vWF, C. Calcium, D. Serotonin', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Vwf REF: Ganong 22"\' ed chapter 27 Platelet has (a) Dense granules: contain the non-protein substances that are secreted in response to platelet activation, including serotonin, ADP, and other adenine nucleotides (b)Alpha granules: contain secreted proteins other than the hydrolases in lysosomes. These proteins include clotting factors and platelet-derived growth factor (PDGF). (c) Platelet membranes contain receptors for collagen, ADP, vessel wall von Willebrand factor , and fibrinogen', 'role': 'assistant'}]