University:
Park University
Course:
BI211 | Human Anatomy and Physiology I
Academic year:

2023
Views:

181

Pages:

9
Author:

1CosmicCrusader

- Blood Supply to kidney RBF & RPF • Relation b/w RBF & Os consumption • Determinants of RBF -Glomerular Capillary Membrane - Determinants of GFR - Use of clearance for measuring GFR & RBF - •Physiological control of GFR & RPF - Regulation of GFR Blood Supply to Kidney 25% C.O. to kidneys medulla < cortex .. Medulla is more Vulnerable to ischemia Renal a Segmental a Interlobal a Arcuate a Interlobular a. Afferent arteriole Glomerulus Efferent arteriole PTCN (vasarecta) #Renal Blood Flow f Renal Plasma Flow RBF = 1250ml/min Kidneys Kidneys recieves 20-25% of co] But as Blood cellp are not filtered :: RPF is of more importance RPF = 55% of RBF RPF = 625ml/min RBF = RPF x 1- Het (Hct *45%) * Relation b/w RBF & D₂ consumption →Depends Depends on Na reabsorption RBFGFR filtration Os consumptioη Na reabsorption O, consumption by kidney Na reab. * Determinants of RBF:- RBF X (Renal artery press) (Renal vein press.) (Total renal vase. resistance) 3-4 mmtug similar to systemic asterial press. •interlobular artery Res.↑ RBF const Res RBF Rest RBF+ Res. RBFL Res.L RBF Res RBFT #Glomerular Capillary Membrane AA EA Fenestratione → Endothelial cell →B.M. Podocytes Silt diaphragm (space b/w footplates/foot processes of adjacent podocytes) Proteins & cellular components are not filtered by GC ① Size barrier Fenestratione i.e. small gaps in capillaries ↓(size :- 4-8nm) Doesnot allows large protein molecules to pars through Charge barier Charge ⇒ • Proteins (-ve) •GC (-ve) Endoth BMO Podocyte Smainly dit proteoglycan (Hepasan sulphate) ③Slit diaphragm formed by food process of podocytes #Determinants of GFR determined by Starling forces Net filtration Press. (NFP) (Glomerular capillary filtration coefficient) •hydraulic conductivity? S.A. of GC Property of GC GFR = Kf x NFP Favoring force 1) Hydrostatic press. in GC (Pc) = 60mmHg starling forces (forces required for filtration) Opposing forces 1) Oncotic press of Go (c) = 32mm Ho 2) Oncotic press in B-C. (8=0) 2) Hydrostatic press in B (PB) = 18 mm Hg GFR = 125 me/min NFP = Favoring - Opposing =(Pc+KB)-(Xc+ PB) = (60+0)-(32+18) = 10mmHg # Use 엌 CLEARANCE to quantify GFR & RBF :- Svolume of plasma completely cleared of a substance by kidneys per unit time. Kidney filters →Inulin cleared INULIN completely from plasma Procedure:- iv. inulin Plasma inulin conc (P) kidneys Filtration :: INULIN is gold standard for measuring GFR →freely filtereol No secretion No reabsorption Clearance (inulin) urine inulin (u) x vol. of urine (v) conc Plasma inulin conc (P) Clearance (inulin) UxV GFR = 125ml/min Practical method for 9ff measurement:- Plasma creatinine JGFR = UV Clearance = GFR •No Secretion No reabsorption Eg:- Inulin PAH is almost completely secreted into renal tubules عالم Gold standard for RPF measurement = PAH #Clearance > GFR → Net secretion Eg:- PAH Clearance

Renal Physiology: Blood Supply

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