Full-size Left-side Hidden
EXTRACELLULAR FLUID DISTRIBUTION BETWEEN PLASMA VOLUME AND INTERSTITIAL LYMPHATIC VOLUME

Control of Fluid Movement Across the Capillary

Regulated flow of fluids through the ECF is essential for maintaining homeostasis. Blood flow delivers oxygen to arterioles, capillaries, and venules and clears waste products of metabolism. A second flow of fluid important to organ function is filtration of plasma across the microcirculation into the interstitial lymphatic compartment of the ECF. Multiple mechanisms regulate this flow and the distribution of ECF between the plasma volume and interstitial lymphatic fluid compartments (see Fig. 5-1). More than 100 years ago Ernest Starling described the hypothesis that there exists a balance of driving forces across the capillary membrane. Starling's hypothesis proposed that elevated hydrostatic pressure in the lumen of the capillary favors the flow of plasma into the interstitium whereas the oncotic pressure generated from protein solutes in plasma favors …