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': 'Conduction along membrane is dependent on all of the following EXCEPT: March 2013 \nSelect and explain. \nA. Ca2+, B. K+, C. Fe2+, D. Na+', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. C i.e. Fe2+ A decrease in extracellular Ca2+ concentration increases the excitability of nerve and muscle cells by decreasing the amount of depolarization necessary to initiate the changes in the Na+ and K+ conductance that produce the action potential. Conversely, an increase in extracellular Ca2+ concentration can stabilize the membrane by decreasing excitability.', 'role': 'assistant'}]