This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Physiology
[{'content': 'Which of the following ions is involved in peripheral oxygen sensing chemoreceptors? \nSelect and explain. \nA. Potassium, B. Calcium, C. Sodium, D. Chlorine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Potassium is involved in peripheral oxygen sensing chemoreceptors. Type I glomus cells (carotid and aoic body) have O2- sensitive K+ channels, whose conductance is reduced in propoion to the degree of hypoxia. This reduces the K+ efflux, depolarising the cell and causing Ca2+ influx. The Ca2+ influx triggers action potentials and consequent excitation of the afferent nerve endings. Ref: Ganong&;s Review of Medical Physiology 26th edition Pgno: 648', 'role': 'assistant'}]