Renal physiology I_ GFR.pdf

07/01/24 Renal physiology I: GFR Learning objective: de ne and describe auto regulation of renal blood ow. Learning objective: de ne what is glomerular ltration rate and how it is regulated. Definitions: RBF- Renal Blood Flow. The volume of blood delivered to the kidneys per unit time. RPF- Renal Pl...

07/01/24 Renal physiology I: GFR Learning objective: de ne and describe auto regulation of renal blood ow. Learning objective: de ne what is glomerular ltration rate and how it is regulated. Definitions: RBF- Renal Blood Flow. The volume of blood delivered to the kidneys per unit time. RPF- Renal Plasma Flow. The volume of plasma delivered to the kidneys per unit time. GFR- Glomerular Filtration Rate. How much uid is squeezed through the glomerular bed per unit time. FF- Filtration Fraction. GFR/RPF x100. RPC- Renal Plasma Clearance. The volume of plasma that is cleared of a known substance per unit time. Because your plasma makes up 55% of your blood, your RPF is 55% of your RBF. How to measure GFR: We need to use a substance that can: Be ltered freely ( smaller than 30000 Daltons ). Not secreted or reabsorbed. Not toxic. Not broken down/ metabolised. GFR UX p V U= solute concentration in the urine. V= volume of urine excreted per minute. P= solute concentration in the plasma. Inulin is the only substance, where GFR and renal clearance are the same value. Because of its complexity, it cannot be used routinely. Overview: