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
"Diluting segment" of a nephron is: 
Select and explain. 
A. Descending limb of loop of Henle, B. Thick ascending limb of loop of Henle, C. DCT, D. Collecting duct
B: Thick ascending limb of loop of Henle
Answer: B: Thick ascending limb of loop of Henle 
Explanation: Thick ascending LOH is k/a the diluting segments of the nephron. It is impermeable to water. It has NKCC cotranspoer proteins that reabsorb Na+, K+, 2Cl- ions. Thus,There is a net reabsorption of solutes with no movement of water, making the tubular fluid that reaches the DCT hypotonic.