Final answer:
Starling forces combine hydrostatic and osmotic pressures to describe fluid movement across capillaries. They are crucial for calculating net filtration pressure, which is the difference between capillary hydrostatic pressure and blood colloid osmotic pressure.
Step-by-step explanation:
Starling forces describe the movement of fluid across capillaries by accounting for the interaction between hydrostatic pressure and osmotic pressure. These forces determine the movement of fluid between blood vessels and the surrounding tissue—out of the capillary at the arteriolar end where the hydrostatic pressure is higher, and into the capillary at the venule end where the osmotic pressure is higher. The values necessary for calculation of the net filtration pressure can be derived from these forces, which equals the difference between capillary hydrostatic pressure (CHP) and blood colloid osmotic pressure (BCOP).