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.