If the interstitial hydrostatic pressure is 2 mm Hg, interstitial oncotic pressure is 7 mm Hg and capillary hydrostatic pressure is 25 mm Hg. What should be the capillary oncotic pressure to allow a net filtration pressure of 3 mm Hg?
(A) 20 (B) 21 (C) 23 (D) 27
(D) Ans: D. 27Formula - GFR = Kf l(PGC- PT) - (7r GC-)I* Kf- Glomerular ultrafiltration coefficient. - Product of glomerular capillary wall hydraulic conductivity (i.e. its permeability) & effective filtration surface area.* PGC - Mean hydrostatic pressure in glomerular capillaries = 25* PT - Mean hydrostatic pressure in tubule (Bowman's space) = 2* GC - Oncotic pressure of plasma in glomerular capillaries* T - Interstitial colloidal oncotic pressure = 7* In this question, - GFR, 3 = Kf Kf Kf . - GC = 27 mm/Hg.