This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Physiology
[{'content': 'True regarding respiratory centre \nSelect and explain. \nA. Directly simulated by fall in PaO2, B. Connected with cardiac center, C. Inhibited during swallowing, D. Situated in midbrain', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The respiratory center is located in the medulla oblongata and is involved in the minute-to-minute control of breathing. Unlike the cardiac system, respiratory rhythm is not produced by a homogeneous population of pacemaker cells Ref: guyton and hall textbook of medical physiology 12 edition page number: 371,372,373', 'role': 'assistant'}]