Final answer:
The initial effect of a blood clot forming on the venous side of a capillary bed is an increase in hydrostatic pressure in the capillary.
Step-by-step explanation:
The initial effect of a blood clot forming on the venous side of a capillary bed is an increase in hydrostatic pressure in the capillary.
This increase in hydrostatic pressure results in a decreased pressure gradient between the capillary and the surrounding tissues.
As a result, there is a decrease in fluid filtration and an increase in fluid reabsorption, leading to a reduced flow of fluid into the interstitial space.