Question

Counter current mechanism in kidney occurs in cortex or medulla of nephron

Answer 1

Hi.

here is your answer. ..

● Mammals have the ability to produce a concentrated urine. The Henley's loop and vaca recta play an important role in in this.

● The flow of filtrate in the 2 limbs of Henley's loop is in the opposite direction and thus forms a counter current.

● The flow of blood through the 2 limbs of vaca recta is also in a current pattern. The proximity between Henley's loop and vaca recta .as well as the counter current in them help in maintaining an increase osmolality towards the inner medullary interstitium ,

● I.e. from 300 mOsmality-1 in the cortex to about 1200 mOsmality -1 in the inner medulla. This gradient is mainly caused by NaCl and urea.

● NaCl is transported by the ascending limb of Henley's loop which is exchanged with the descending limb of vaca recta.

● Similarly small amountsof urea enter the thin segment of the ascending limb of Henley's loop which is transported back to the interstitium by the collecting tubules.

● The above described transported of substance facilitied by the special arrangements of Henley's loop & vaca recta is called counter current mechanism.



● This mechanism helps to maintain a concentration gradient in the medullary interstitium.


● Presence of such interstitial gradient helps in an easy passage of water from the collecting tubules thereby concentrateing than the filtrate.



hope it helps you ☺

Answer 2

It occurs in medulla of nephron