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': 'TRUE regarding human heart \nSelect and explain. \nA. Conduction of impulse from endocardium to inwards, B. During exercise duration of systole is reduced more than diastole, C. HR increases with parasympathetic denervation, D. Vagal stimulation decreases force of contraction', 'role': 'user'}, {'content': 'Answer: C \nExplanation: In resting state, the heart is under vagal control. But when there is vagal denervation, the sympathetic activity is unhindered and the heart rate increases.\nConduction is from endocardium to epicardium.\nDuring exercise, the duration of diastole is more decreased than systole.\nVagal stimulation does not decrease the force of contraction.', 'role': 'assistant'}]