Final answer:
The colloid osmotic pressure in the renal corpuscle draws fluid into the capillaries from Bowman's space, balancing hydrostatic pressure and enabling reabsorption of water.
Step-by-step explanation:
Within the renal corpuscle, the colloid osmotic pressure (COP) is a pressure drawing fluid into the capillaries. The blood colloidal osmotic pressure (BCOP) is generated by the plasma proteins that cannot cross the semipermeable capillary cell membrane.
This generates a higher colloidal concentration in the blood compared to tissue fluid, creating an osmotic gradient that attracts water back into the bloodstream from the Bowman's space (the lumen within Bowman's capsule) where the osmotic pressure is near zero due to the absence of proteins. Consequently, COP is a significant force for water reabsorption in the kidneys, balancing the hydrostatic pressure that pushes water out of the capillaries.