This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Conducting System of Hea, Subject name: Physiology
[{'content': '"Gate" cells in the hea are: \nSelect and explain. \nA. Cells in SA node, B. Cells in AV node, C. Cells in his bundle, D. Cells in Purkinje fibers', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Purkinje fibers at the apex, where impulse is passed on from Purkinje fibers to ventricular muscle, are the so-called "gate cells".', 'role': 'assistant'}]