Final answer:
The greatest percentage of water in the extracellular compartment is represented by the interstitial fluid, which surrounds cells that are not blood cells and accounts for a significant portion of the body's extracellular fluid volume. Option a.
Step-by-step explanation:
The question asks which compartment represents the greatest percentage of water in the extracellular space. Based on the provided information, the answer would be the interstitial fluid (IF), as it constitutes the second largest volume of water in the body after the intracellular fluid.
Extracellular Fluid Distribution
The human body's water content can be split into two major compartments: intracellular fluid (ICF) and extracellular fluid (ECF). The ICF represents about 60% of the total water in the body, primarily located within cells. The ECF, making up the rest, is found outside the cells and includes plasma and interstitial fluid. The interstitial fluid is the component that bathes and surrounds all cells not in the blood, accounting for approximately 15% of body weight in a lean person. The plasma, forming part of the blood, represents about 5% of body weight. Transcellular fluid, which refers to fluids such as cerebrospinal fluid (CSF), ocular fluid, lymph, and synovial fluids, contributes a relatively minor volume in comparison.
Thus, the correct answer is A) interstitial volume, as it constitutes a larger percentage of the extracellular fluid compared to plasma or transcellular volumes.