Which of the following is the chief ion used to maintain the volume of fluid outside cells?Question 45Answera.chlorideb.sodiumc.calciumd.potassium

Chief Ion for Fluid Volume Maintenance

The chief ion used to maintain the volume of fluid outside cells is primarily sodium (Na⁺). Sodium plays a crucial role in regulating extracellular fluid volume, osmotic pressure, and overall fluid balance in the body. It is a major cation found in extracellular fluid and is involved in various physiological processes, including nerve impulse conduction and muscle contraction.

Here’s a breakdown of the options:

1. Chloride (Cl⁻): Primarily helps maintain osmotic balance but is not the chief ion.
2. Sodium (Na⁺): The principal ion for maintaining extracellular fluid volume and osmotic pressure.
3. Calcium (Ca²⁺): Important for muscle contraction and signaling but not the chief extracellular fluid volume regulator.
4. Potassium (K⁺): Predominantly found inside cells and important for intracellular processes.

Final Answer

b. sodium