Question

As glomerular filtrate moves through the ascending Loop of Henle, the filtrate becomes more dilute. Why?

Select one:

a. The ascending loop of Henle is pumping out ions but impermeable to water

b. The ascending loop of Henle is permeable to water, water flows out of tubule

c. The ascending loop of Henle is permeable to water and ions, ions flow out of tubule

d. The ascending loop of Henle is impermeable to water and ions

Answer 1

Option a- The ascending loop of Henle is pumping out ions but impermeable to water.

As the Glomerula Filtrate moves from PCT ,it reaches the descending portion of the Henles Loop .This Portion is extremely permeable to water But less permeable to ions.So , here water is easily reabsorbed and solutes are not reabsorbed.------This causes Urine to be More Concentrated.

But When Filtrate reaches ascending loop of Henle,Permiability of the Loop Changes.This Ascending limb of Henles loop is Impermiable to Water & Permiable to Ions.So there will be Reabsorption of ions Like Na+, K+ and Cl− ions .[By Na+K+-2Cl- Cotransport].

This movement of Ions Outside the Filtrate[Reabsorption],Makes Urine more Diluted.

Since this Loop is Impermiable to Water,Water cannot be re absorbed here.