How does the loop of Henle enable the mammalian kidney to produce hypertonic urine?
I-The ascending limb of the loop actively extrudes Na+.
II-The descending limb interacts with the ascending limb to raise the osmolarity of the extracellular fluid in the renal medulla.
III-The concentration is further enhanced by the presence of urea,which draws water out of the collecting ducts by osmosis.
A)just I
B)II and III
C)just III
D)I and II
E)I,II,and III

Question

How does the loop of Henle enable the mammalian kidney to produce hypertonic urine? 
I-The ascending limb of the loop actively extrudes Na+.
II-The descending limb interacts with the ascending limb to raise the osmolarity of the extracellular fluid in the renal medulla.
III-The concentration is further enhanced by the presence of urea,which draws water out of the collecting ducts by osmosis.
A)just I
B)II and III
C)just III
D)I and II
E)I,II,and III

Quizplus · Accepted Answer

The loop of Henle consists of a descending limb and an ascending limb that work together to create a hypertonic environment in the renal medulla. The ascending limb actively extrudes Na+ to create a concentration gradient, while the descending limb interacts with the ascending limb to raise the osmolarity of the extracellular fluid in the renal medulla. This results in a concentration gradient that draws water out of the collecting ducts by osmosis, which is further enhanced by the presence of urea. Therefore, choices I, II, and III are all correct and contribute to the loop of Henle's ability to produce hypertonic urine.

How Does the Loop of Henle Enable the Mammalian Kidney