The Major Cation in Extracellular Fluid Is

Question

The major cation in extracellular fluid is
A) sodium.
B) potassium.
C) calcium.
D) magnesium.
E) iron.

Accepted Answer

Sodium is the major cation in extracellular fluid, accounting for approximately 90% of the cations. Potassium is the major cation in intracellular fluid. Calcium and magnesium are also important electrolytes, but they are present in smaller amounts in extracellular fluid. Iron is not an electrolyte and has no role in maintaining fluid balance.