This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Physiology
Pancreatic juice becomes thick if it has impaired 
Select and explain. 
A. Na secretion, B. Cl- secretion, C. Na+ H+ exchange, D. H+ secretion
B: Cl- secretion
Answer: B: Cl- secretion 
Explanation: As the volume of pancreatic secretion increases, its Cl- concentration falls and its HCO3- concentration increases.The magnitude of the exchange is inversely propoionate to the rate of flow.In cystic fibrosis where this exchange mechanism is lost, pancreatic secretions become dehydrated and thickenedREF: GANONG&;S REVIEW OF MEDICAL PHYSIOLOGY, TWENTY-THIRD EDITION, PAGE NO:435,436