NEETZoologyExcretory Products and their Elimination
In a hypothetical mammal, the kidneys possess exclusively cortical nephrons with no juxtamedullary nephrons. Which of the following would be the direct consequence on its excretory system?
Options
- AThe vasa recta would be highly reduced or absent, resulting in an inability to produce highly concentrated uri
- BThe vasa recta would become highly developed in the cortex to compensate for the short loops of Henle.
- CThe counter current mechanism would operate exclusively in the cortex to maintain the medullary osmotic gradie
- DThe osmotic gradient in the inner medulla would still reach 1200 mOsmol L ⁻¹ due to active transport by the co
Correct answer
A. The vasa recta would be highly reduced or absent, resulting in an inability to produce highly concentrated uri
Step-by-step solution
In cortical nephrons, the loop of Henle is too short and extends only very little into the medulla. Furthermore, the vasa recta is absent or highly reduced in these nephrons. The counter current mechanism, which is responsible for creating and maintaining the high osmolarity of the inner medullary interstitium (up to 1200 mOsmol L ⁻¹ ), strictly relies on the long loops of Henle of juxtamedullary nephrons and the accompanying vasa recta extending deep into the medulla. Without these structures, the medullary osmoti