This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Excretory System (Kidney, Bladder) Acid-Base Balance, Subject name: Physiology
[{'content': 'In which of the mentioned segments of a nephron, Na+ reabsorption primarily occurs by the Na+-H+ exchange? \nSelect and explain. \nA. PCT, B. loop of Henle, C. DCT, D. Collecting duct', 'role': 'user'}, {'content': 'Answer: A \nExplanation: In the PCT, the apical membrane has Na+/H+-antipoer, which couples H+ secretion with the Na+ movement across the apical membrane. In the TAL of loop of Henle:- The sympoer NKCC moves 1 Na+, 1 K+, 2 Cl- through the apical membrane into the cell. In DCT:- The sympoer is NCC. In the late distal tubule and collecting duct:- Na+diffuses across the apical membrane through the epithelial Na+ channel (ENaC).', 'role': 'assistant'}]