Which equation accurately represents fluid compartments in the body?

Fluid compartments in the body can be understood through the relationships between extracellular fluid, intracellular fluid, and plasma volume. The body’s total fluid compartments are divided primarily into intracellular fluid (inside the cells) and extracellular fluid (outside the cells), which includes interstitial fluid and plasma volume.

The correct representation emphasizes the interrelationship within these compartments. Specifically, plasma volume is a component of extracellular fluid; therefore, interstitial fluid and plasma volume together make up the entire extracellular fluid volume. The equation delineates the fluid dynamics accurately by illustrating that plasma volume can be derived from understanding the differences between extracellular and interstitial fluids.

Other aspects of the choices involve mathematical relationships but do not correctly represent the standard anatomical and physiological definitions of fluid compartments. For instance, volume relationships for total body fluid must include all components without misrepresenting their connections. Thus, the accurate presentation reflects the established frameworks in physiology regarding how these fluids are compartmentalized in the body.