Mechanism Of Concentration Of Filtrate

Question 1

Which structures play a significant role in the ability of mammals tp produce a concentrated urine?

Answer 1

Henle’s loop

Vasa recta

Question 2

Direction of flow of filtrate in Henle’s loop?

Answer 2

Opposite direction in the two limbs

This forms a counter current

Question 3

Direction of flow of filtrate in vasa recta?

Answer 3

The flow of blood through the two limbs of vasa recta is also in a counter current pattern.

Question 4

What effect does the proximity between the Henle’s loop and vasa recta have?
What other factor helps?

Answer 4

In maintaining an increasing osmolarity towards the inner medullary interstitium
Counter current in Henle’s loop and vasa recta

Question 5

Value of osmarity gradient?

Main cause?

Answer 5

300 mOsmol/L in the cortex to about 1200 mOsmol/L in the inner medulla
NaCl and urea

Question 6

What is counter current mechanism?

Answer 6

NaCl is transported by the ascending limb of Henle’s loop which is exchanged with the descending limb of vasa recta.
NaCl is returned to the interstitium by the ascending portion of vasa recta. Similarly, small amounts of urea enter the thin segment of the ascending limb of Henle’s loop which is transported back to the interstitium by the collecting tubule.
The above described transport of substances facilitated by the special arrangement of Henle’s loop and vasa recta is called the counter current mechanism

Question 7

What does the counter current mechanism help in?

Answer 7

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 tubule thereby concentrating the filtrate (urine). Human kidneys can produce urine nearly four times concentrated than the initial filtrate formed.

Question 8

Concentration of urine to initial filtrate formed

Answer 8

Human kidneys can produce urine nearly four times concentrated than the initial filtrate formed.