The increase in osmotic gradient in the inner medullary interstitium compared to the outer medulla is mainly caused by
A) NaCl
B) Urea
C) Glucose
D) KCl
E) proteins

Question

Quizplus · Accepted Answer

The increase in osmotic gradient in the inner medullary interstitium compared to the outer medulla is mainly caused by urea. Urea is actively transported into the medullary interstitium by the collecting ducts, contributing significantly to the high osmolarity in the inner medulla, which is essential for the kidney's ability to concentrate urine.

The Increase in Osmotic Gradient in the Inner Medullary Interstitium