Topics:
Animal Nutrition, Animal Refresher
Major Ions in Extra-Cellular Fluid
Major cation & anion in extra-cellular fluid (ECF) are:
- $Na^{+}$, $Cl^{-}$ — Correct Answer
- $K^{+}$, $PO_{4}^{-}$
- $Na^{+}$, $PO_{4}^{-}$
- None
Explanation:
Correct Answer: Na⁺, Cl⁻
The major cation in Extra-Cellular Fluid (ECF) is Na⁺ (Sodium) and the major anion is Cl⁻ (Chloride). ECF includes blood plasma, interstitial fluid, and lymph. This ionic composition is critical for maintaining osmotic balance and nerve conduction.
Fluid Compartment Ion Composition
| Fluid Compartment | Major Cation | Major Anion |
|---|---|---|
| Extra-Cellular Fluid (ECF) | Na⁺ | Cl⁻ |
| Intra-Cellular Fluid (ICF) | K⁺ | PO₄³⁻ |
Clinical Relevance
- Hyponatraemia (low ECF Na⁺) leads to oedema, weakness, and neurological signs.
- Na⁺/K⁺-ATPase pump actively maintains this electrochemical gradient across cell membranes.
- Dietary NaCl (common salt) directly replenishes ECF Na⁺ and Cl⁻.
Why Other Options Are Wrong
- K⁺, PO₄³⁻ → these are the ICF ions, not ECF.
- Na⁺, PO₄³⁻ → Na⁺ is correct for ECF cation, but the anion is Cl⁻, not PO₄³⁻.
- None → incorrect; ECF has well-defined major ions.
📚 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.
