In which portion of her kidney tubule is most of the water being reabsorbed

[Oak]

A healthy 38-year-old woman is found unconscious and severely dehydrated. Her plasma levels of antidiuretic hormone (ADH) are increased about 5-fold above normal. In which portion of her kidney tubule is most of the water being reabsorbed?

A. Cortical collecting duct
B. Distal tubules
C. Loops of Henle
D. Medullary collecting duct
E. Proximal tubule

[dr_ravi]

Ans:E. Proximal tubule
Because About 65% of the water filtered by the glomeruli (180 L/day) is reabsorbed in the proximal tubule.
15% loop of henle
10% distal tubule.
less than 10% in the collecting ducts


The amount of water reabsorbed in the proximal tubule and loop of Henle is not affected by ADH, because ADH does not affect tubular permeability in these segments of the nephron.

[bharat]

Originally Posted by dr_ravi

Ans:E. Proximal tubule
Because About 65% of the water filtered by the glomeruli (180 L/day) is reabsorbed in the proximal tubule.
15% loop of henle
10% distal tubule.
less than 10% in the collecting ducts


The amount of water reabsorbed in the proximal tubule and loop of Henle is not affected by ADH, because ADH does not affect tubular permeability in these segments of the nephron.

well what u have told is same that i aslo mean it's PCT where water absorptin is max. despite of ADH but in case of ADH
may be distal part of distal convulated tube le about 10% absorve garche hoala ni haine te aru collecting duct ko bhanda?
hope correct answer is E

[Oak]

Thats right the correct answer is E.

About 65% of the water filtered by the glomeruli (180 L/day) is reabsorbed in the proximal tubule, 15% in the loops of Henle (choice C), 10% in the distal tubules (choice B), and less than 10% in the collecting ducts (choices A and D); about 1 L of water is normally excreted as urine each day.

The amount of water reabsorbed in the proximal tubule and loop of Henle is not affected by ADH, because ADH does not affect tubular permeability in these segments of the nephron. However, ADH increases the permeability of the distal tubules and collecting duct, which increases reabsorption of water.

When ADH levels are high, the urine output can decrease to less than 0.5 L/day; when ADH levels are low, the output of urine can increase to more than 30 L/day. Even at these extremes, however, most of the water in the glomerular filtrate is still reabsorbed in the proximal tubule.