Bowman's Capsule

In order to understand glomerular filtration, it's necessary to see that the glomerular Starling's Forces are only half of the story. The glomerulus is surrounded by the Bowman's capsule, and filtrate is forced into the Bowman's capsule. Fluid exchange in the Bowman's capsule is governed by the same Starling's forces operating in the glomerulus. That is, the fluid there also exerts a hydrostatic pressure and it, in effect, opposes the hydrostatic pressure coming from the glomerulus.

In theory there should be virtually no plasma proteins in the Bowman's capsule, since blood cells and plasma proteins should not be filtered from the glomerulus.