mechansim of Aqueous production- diffusion-Main mechanism , energy dependent process ultra-filtration Active secretion Ultrafiltration, most of the plasma substances pass out from thecapillary wall. Active Secretion Paired Na+/H+and Cl-/HCO3-antipos actively transpos Na+ and Cl- from the stroma into the cells. Intercellular gap junctions also play critical rule. The tight junctions between the cells of the non-pigment epithelium create pa of blood aqueous barrier. Ceain substances are actively transpoed (secreted) across this barrier into posterior chamber. The active transpo is brought about by Na+ -K+ activated ATPase pump, calcium and voltage gated ion channels and carbonic anhydrase enzyme system. Diffusion. Active transpo of these substances across the non-pigmented ciliary epithelium results in an osmotic gradient leading to the movement of other plasma constituents into the posterior chamber Formation of aqueous humour