A desert mammal can produce very concentrated urine because it has
- A. a larger Bowman's capsule
- B. more glomeruli per kidney
- C. a much longer loop of Henle, which builds a steeper salt gradient in the medulla
- D. no collecting ducts
Explanation
The loop works as a countercurrent multiplier, making the medulla progressively saltier towards the tip, and the collecting duct passing through that region loses water by osmosis. A longer loop maintains a steeper gradient, so more water can be withdrawn and the urine leaves more concentrated, which is exactly the adaptation seen in the kangaroo rat. Filtration rate is unrelated to how concentrated the final urine is.
Related questions
Ultrafiltration in the glomerulus is driven by
Which of the following is normally absent from glomerular filtrate?
All the glucose in the filtrate is normally reabsorbed in the
Antidiuretic hormone controls the water content of the blood by
A patient passes very large volumes of dilute urine but the urine contains no glucose. The most likely condition is