Question

The given figure shows re-absorption and secretion of major substances at different parts of the nephron. The movement of which of the following substances is wrongly depicted?

• A. $NaCl$ and $K^{+}$ at $DCT$
• B. $NaCl$ and $N{H}_3$ at $PCT$
• C. $NaCl$ at ascending limb of loop of Henle
• D. $H_{2}O$ at descending limb of loop of Henle

Answer 1

Answer: (B)

$NaCl$ and $N{H}_3$ at $PCT$

In the proximal convoluted tubule, maximum reabsorption of ions takes place e.g. $H^{+}$, $N{a}^{+}$, $K^{+}$, $C{l}^{-}$, $N{H}_3$, etc.

The movement of $N{a}^{+}$,$C{l}^{-}$, and $N{H}_3$ are incorrect and shown inverted. Sodium and Chlorine ions gets reabsorbed from the PCT into the capillaries, and Ammonia gets secreted from the capillaries into the PCT.

Thus, the correct answer is (B).