Final answer:
Body water in the intravascular fluids is located in the blood plasma, which is part of the extracellular fluid. The extracellular fluid is divided into the interstitial fluid and blood plasma, with the latter functioning within the blood vessels to transport substances throughout the body.
Step-by-step explanation:
Body water that is part of the intravascular fluids is located in the blood plasma, which is a component of the extracellular fluid (ECF). The ECF is composed of two primary constituents: the interstitial fluid (IF) and the blood plasma. The IF is the extracellular fluid between the cells, and the blood plasma is the part of the ECF that resides within the blood vessels. This plasma facilitates the transport of materials between cells and the plasma in the capillaries through the IF.
Water makes up approximately 50-70% of an adult's body weight, distributed among different fluid compartments. The intracellular fluid (ICF) compartment includes all fluid enclosed within cells, representing about 60% of the total body water. Conversely, the ECF, which includes blood plasma, represents about 20% of the body weight. These fluids, alongside other ECF components like cerebrospinal fluid, lymph, and synovial fluid, are all outside of cells and hence part of the ECF compartment.