Question

Which of the following diagrams is correct with regard to the proximal (P) and distal (D) tubule of the nephron?

• A.
• B.
• C.
• D.

Hint:

In the nephron, the proximal tubule reabsorbs a large portion of solutes, while the distal tubule fine-tunes ion and pH balance. Pay attention to these key functions when analyzing nephron diagrams.

Answer 1

The Correct Option is C

The proximal tubule (P) is primarily responsible for reabsorbing a large portion of the filtrate, including water, sodium chloride, bicarbonate, and other nutrients. It also secretes hydrogen ions (H+) for acid-base balance. The distal tubule (D) is involved in the fine-tuning of ion exchange and pH balance. It reabsorbs sodium and bicarbonate, and secretes potassium (K+) and hydrogen ions. Looking at the diagrams, option (3) accurately reflects the processes occurring in both the proximal and distal tubules of the nephron. Thus, the correct diagram is option (3).