If Henle's loop were absent from mammalian nephron, which of the following is to be expected : -
A
There will be no urine formation
B
There will be hardly any change in the quality and quantity of urine formed
C
The urine will be more concentrated
D
The urine will be more dilute
The answer is D.
Solution
The loop of Henle, together with the vasa recta, sets up the counter-current mechanism that builds an increasing osmotic gradient in the medullary interstitium (from about 300 mOsm/L in the cortex to about 1200 mOsm/L in the inner medulla). This gradient allows water to be reabsorbed from the collecting duct, which produces a concentrated (hypertonic) urine. Mammals can thus conserve water. Without the loop of Henle, no medullary gradient would form. Water could not be withdrawn from the collecting duct, so a large volume of dilute urine would be formed. Filtration would still occur, so urine would still be produced. So if Henle's loop were absent, the urine would be more dilute.
ConceptRole of loop of Henle in concentrating urine
Mechanism of Concentration of Filtrate in past papers
2 questions from this chapter have appeared across 2 exam years.
