Question

Why does the glomerular filterate become more dilute as it moves through the ascending loop of Henle?

• A. The ascending loop of Henle is permeable to water and ions
• B. The ascending loop of Henle is permeable to ions but impermeable to water
• C. The ascending loop of Henle is impermeable to water and ions
• D. The ascending loop of Henle is permeable to water but not to ions

Answer 1

The correct option is B The ascending loop of Henle is permeable to ions but impermeable to water

The descending loop of Henle is permeable to water; the ascending loop is impermeable.
The descending limb of loop of Henle is permeable to water but almost impermeable to electrolytes. This concentrates the filtrate as it moves down. The ascending limb is impermeable to water but allows transport of electrolytes actively or passively. Therefore, as the concentrated filtrate pass upward, it gets diluted due to the passage of electrolytes to the medullary fluid.