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 effects of sympathetic stimulation, EXCEPT: \nSelect and explain. \nA. Increased conduction velocity, B. Increased hea rate, C. Increased refractory period, D. Increased contractility of hea', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C i.e. Increased refractory periodEffect of sympathetic system on hea mediated by Pi and (ix receptorsSA nodeIncrease in hea rateA.V. nodeIncrease in conduction velocityHis- Purkinje systemIncrease in conduction velocityAtriaIncrease in contractility & conduction velocityVentriclesIncrease in contractility', 'role': 'assistant'}]