Question

Which of the following ions are actively secreted into the filtrate by tubular cells of nephron during urine formation?

• A. $\text{N}\text{H}_{3}\text{, }\text{H}^{+}\text{, N}\text{a}^{+}$
• B. $\text{N}\text{a}^{+}\text{, }\text{K}^{+}\text{, N}\text{H}_{3}$
• C. $K^{+}\text{, }\text{H}^{+}\text{, HC}\text{O}_{3}^{-}$
• D. $K^{+}\text{, N}\text{H}_{3}\text{, }\text{H}^{+}$

Answer 1

Answer: (D)

Tubular secretion is one of the step of urine formation which mainly occurs by cells of $\text{PCT}$ and $\text{DCT}$ of nephrons. The selective secretion of harmful and nitrogenous wastes such as $K^{+},H^{+},N H_{3}$ , etc., from blood to filterate takes place by tubular cells of nephron.