Question

The process of tubular secretion adds following substances to the renal fluid EXCEPT .............

• A. hydrogen ions
• B. creatinine
• C. potassium ions
• D. sodium ions

Hint:

Tubular secretion is important for removing excess waste products and maintaining electrolyte balance in the body. Sodium is reabsorbed, not secreted.

Answer 1

The Correct Option is D

Step 1: Understanding tubular secretion.
Tubular secretion is the process by which substances are added to the renal fluid from the blood, typically in the distal tubules of the kidneys. This process includes the secretion of hydrogen ions, creatinine, and potassium ions, which are vital in regulating the body's fluid and electrolyte balance.
Step 2: Analyzing the options.
(A) hydrogen ions: Correct. Hydrogen ions are secreted into the renal fluid to help maintain pH balance in the body.
(B) creatinine: Correct. Creatinine is a waste product excreted by the kidneys and is secreted into the renal fluid.
(C) potassium ions: Correct. Potassium ions are also secreted during tubular secretion to regulate electrolyte balance.
(D) sodium ions: Incorrect. Sodium ions are reabsorbed, not secreted, during the tubular secretion process.
Step 3: Conclusion.
The correct answer is (D) sodium ions, as sodium ions are reabsorbed rather than secreted in the kidneys.