Processing of Filtrate in the Proximal and Distal Tubules

Question

Processing of filtrate in the proximal and distal tubules
A) achieves the sorting of plasma proteins according to size.
B) achieves the conversion of toxic ammonia to less toxic urea.
C) maintains homeostasis of pH in body fluids.
D) regulates the speed of blood flow through the nephrons.
E) reabsorbs urea to maintain osmotic balance.

Accepted Answer

The proximal and distal tubules play a vital role in maintaining the homeostasis of pH in body fluids through reabsorption and secretion of hydrogen and bicarbonate ions.

Answer: B
 The conversion of toxic ammonia to less toxic urea occurs in the liver, but both the proximal and distal tubules contribute to the excretion of urea from the body.

Answer: E
 The reabsorption of urea in the kidneys helps to maintain osmotic balance in the body fluids, but this occurs primarily in the loop of Henle rather than the proximal and distal tubules.

Therefore, the best choice is C only.