Question

Which one is true?
Urine is hypertonic in distal convoluted tubule
When urine passes into collecting tubule it becomes hypotonic
Urine is isotonic in proximal convolute tubule
Urine becomes more and more hypotonic as it passes through Henles loop

• A. 1 and 4
• B. 1, 2, 3
• C. 2, 3
• D. 3

Answer 1

The correct option is D 3

The proximal tubule can be anatomically divided into two segments:- T he proximal convoluted tubule and the proximal straight tubule. The solutes are absorbed isotonically, in that the osmotic potential of the fluid leaving the proximal tubule is the same as that of the initial glomerular filtrate. However, glucose, amino acids, inorganic phosphate, and some other solutes are reabsorbed via secondary active transport through co-transport channels driven by the sodium gradient out of the nephron.

So, the statement 'Urine is isotonic in proximal convoluted tubule' is True.