Question

How is the presence of an interstitial gradient helpful in urine formation?

Answer 1

Role of interstitial gradient:

1. The tissue that lies between the vasa recta and the loop of Henle is referred to as the interstitium.
2. An interstitial gradient makes it easier for water to exit the collecting tubule, which concentrates the filtrate (urine).
3. It raises the permeability of both water and urea, enabling urea to passively move down its concentration gradient into the interstitial fluid.
4. The accumulation of solutes, mostly NaCl and urea, create this gradient.
5. A concentration gradient in the medullary interstitium is maintained by a counter-current mechanism.