Topics:
Animal Nutrition, Animal Refresher
Excretion Pathways for Sodium and Potassium
Main path of excretion of Ca & P is faeces, while the main path of excretion of $Na^{+}$ & $K^{+}$ is:
- Faeces
- Urine — Correct Answer
- Sweat
- None
Explanation:
Correct Answer: Urine
While Ca and P are primarily excreted via faeces, the mineral ions Na⁺ and K⁺ are primarily excreted via urine. This difference reflects the renal regulation of monovalent ions and the intestinal/biliary secretion pathway for divalent minerals.
Excretion Pathways of Key Minerals
| Mineral | Primary Excretion Route | Exception |
|---|---|---|
| Ca, P | Faeces | In carnivores, P → urine |
| Na⁺, K⁺ | Urine | — |
| Mg | Faeces + Urine | — |
Hormonal Regulation
- Aldosterone (adrenal cortex) regulates Na⁺ reabsorption and K⁺ excretion in renal tubules.
- The kidneys are the primary site of Na⁺/K⁺ homeostasis.
- Sweat contains Na⁺ and K⁺ but is not the primary excretory route.
Why Other Options Are Wrong
- Faeces → the route for Ca and P, not Na⁺/K⁺.
- Sweat → a minor route; not the primary excretion pathway.
- None → urine IS the correct answer.
📚 About this Topic — Animal Nutrition
This multiple choice question is from Animal Nutrition, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Nutrition to strengthen your preparation.
