Fluid & Electrolyte Q 32

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The interstitial space holds approximately how many liters?

  

    A. 3 L

    B. 6 L

    C. 9 L

    D. 12 L

    

    

Correct Answer: C. 9 L

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The interstitial space holds 9 L. The extracellular fluid comprises approximately 20% of total body weight and further sub categorized as plasma at approximately 5% of body weight and interstitial space which is approximately 12% of body weight.

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Option A: Extracellular fluid and interstitial fluid are similar in composition. Extracellular spaces contain high concentrations of sodium, chloride, bicarbonate, and proteins but are relatively lower in potassium, magnesium, and phosphate. Interstitial fluids physiologically tend to have a low concentration of proteins.

Option B: The distribution of fluid throughout the body can be broken down into two general categories: intracellular fluid and extracellular fluid. Intracellular fluid is approximately 40% of the total body weight. It is the total space within cells primarily defined as the cytoplasm of cells. In general, intracellular fluids are stable and do not readily adjust to rapid changes.

Option D: Fluid is always in flux through a variety of regulatory mechanisms to maintain appropriate concentrations throughout the various compartments of the body. Fluid is largely regulated through passive diffusion following the concentration gradients of osmotically active solutes; however, hydrostatic pressures can influence fluid movement between spaces.

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