Capsular hydrostatic pressure (CHP) is a back-pressure that opposes filtration. As the filtrate is forced into the capsular space, it meets 2 forms of resistance: the wall of the capsule and the fluid that has already filled the renal tubule.
This pressure drives fluid out of the capillary (i.e., filtration), and is highest at the arteriolar end of the capillary and lowest at the venular end.
