Topics:
Animal Nutrition, Animal Refresher
Major Ions of Intracellular Fluid
The major cation & anion of intracellular fluid (ICF) are respectively:
- $Na^{+}$, $Cl^{-}$
- $K^{+}$, $PO_{4}^{-}$ — Correct Answer
- $Na^{+}$, $PO_{4}^{-}$
- None
Explanation:
Correct Answer: K⁺, PO₄³⁻
The major cation of Intracellular Fluid (ICF) is K⁺ (Potassium) and the major anion is PO₄³⁻ (Phosphate). Intracellular fluid is the fluid inside cells, comprising about 60–70% of total body water.
Fluid Compartment Electrolytes — Summary
| Fluid | Major Cation | Major Anion |
|---|---|---|
| Extracellular Fluid (ECF) | Na⁺ | Cl⁻ |
| Intracellular Fluid (ICF) | K⁺ | PO₄³⁻ |
Key Body Water Facts
- Total body water: 60–70% of animal body
- ICF makes up ~2/3 of total body water
- ECF makes up ~1/3 of total body water
- Na⁺/K⁺-ATPase pump maintains these gradients: pumps 3 Na⁺ out and 2 K⁺ in per cycle
Phosphorus — Special Role
- Phosphorus plays an important role in nucleotide formation: ATP, ADP
- Bone Ca:P ratio = 2:1
- Normal blood phosphorus in ruminants: 4–8 mg/dl
Why Other Options Are Wrong
- Na⁺, Cl⁻ → these are ECF electrolytes, not ICF
- Na⁺, PO₄³⁻ → Na⁺ is ECF cation; PO₄³⁻ is ICF anion; the pairing is mixed/incorrect
- None → incorrect; K⁺ and PO₄³⁻ are the established ICF electrolytes
📚 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.
