The vertical osmotic gradient in the kidney
A) is established and maintained by the countercurrent system.
B) makes it possible to put out urine of variable concentration depending on the needs of the body by varying the degree of water permeability of the distal portions of the nephron.
C) is found in the renal cortex.
D) both (a) and (b) above.
E) all of these answers.

Question

Quizplus · Accepted Answer

The vertical osmotic gradient in the kidney is established and maintained by the countercurrent system, which involves the loop of Henle and vasa recta. This gradient makes it possible to put out urine of variable concentration depending on the needs of the body by varying the degree of water permeability of the distal portions of the nephron. The gradient is found in the renal medulla, not the cortex. Therefore, both options (a) and (b) are correct, making (d) the correct answer.

The Vertical Osmotic Gradient in the Kidney