Question

9. Which part of the human kidney has a higher concentration of urea and salts (the renal cortex or the renal medulla)? Why is important for this region of the human kidney to have a higher concentration of urea/salts? (2 marks)

Answer 1

question 9

Urea is primarily absorbed in the deep inner medulla. Urea serves a second function in the medulla: it is the major source for excretion of nitrogenous waste; large quantities of urea need to be excreted daily. A high interstitial urea concentration also serves to osmotically balance urea within the collecting duct lumen. The urea reabsorbed increases the medullary concentration of the solute, which is critical for the reabsorption of water from the thin inner medullary part of the descending limb of the loop of Henle.