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': 'Maximum number of sodium channels per square micrometer, is present in: March 2009 \nSelect and explain. \nA. Cell body, B. Axon terminal, C. Surface of myelin, D. Nodes of Ranvier', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. D: Nodes of RanvierIn a myelinated neuron, number of sodium channels per square micrometer is:Cell body-50-75Axon terminal-20-75Surface of myelin-Less than 25Nodes of Ranvier-2000-12,000In the initial segment:350-500In unmyelinated neurons, number is about 110', 'role': 'assistant'}]