Which of the following statements about extracellular fluid are true?
A. The total extracellular fluid volume represents 40% of the body weight. B. The plasma volume constitutes one fourth of the total extracellular fluid volume C. Potassium is the principal cation in extracellular fluid. D. The protein content of the plasma produces a lower concentration of cations than in the interstitial fluid E. The interstitial fluid equilibrates slowly with the other body compartments.
The plasma volume constitutes one fourth of the total extracellular fluid volume
The total extracellular fluid volume represents 20% of body weight. The plasma volume is approximately 5% of body weight. Sodium is the principal cation. The Gibbs-Donan equilibrium equation explains the higher total concentration of cations in plasma. Except for joint fluid and cerebrospinal fluid, the majority of the interstitial fluid exists as a rapidly equilibrating component.