In the capillaries, hydrostatic pressure (hp) is exerted by blood pressure. The hydrostatic force is the main driving force for fluid transport between the tissues and the capillaries. It is the pressure that is exerted by any fluid that is in a closed system. So, for blood or capillary hydrostatic pressure, it is the pressure exerted by the blood in the capillaries. Without this pressure, there would be no flow of blood and nutrients in the system of the body so no life would be sustained. As a fluid exits the capillary moving into the tissues, the hydrostatic pressure increases.
