Difficulty: Medium
Average Score: 95%
Simulated
In the kidney, where are the mechanisms found that are responsible for increasing urine concentration?
Correct answer
D
Rationale
The loop of Henle (D) creates a hypertonic medullary gradient via countercurrent multiplication, concentrating urine. Calyx (A) and renal pelvis (C) collect urine. Proximal tubule (B) reabsorbs nutrients, not concentrates urine.