Renal 2

Question 1

Pathogenesis of Goodpasture syndrome?

Answer 1

Anti-GBM antibodies (IgG) target collagen type 4 in the glomerular basement membrane, w/ subsequent complement (C3) deposition. The anti-GBM antibodies may cross-react w/ collagen type 4 in pulmo alveolar basement membrane, resulting in pulmo hemorrhage.
>Sx: hematuria, hemoptysis

Question 2

What 3 ways do kidneys try to correct metabolic acidosis?

Answer 2

1) Inc. HCO3- reabsorption (proximal tubules).
2) Inc. H+ secretion (H-ATPase, H/K-ATPase).
3) Inc. acid buffer excretion (HPO4, NH3) – allow secretion of H+ in greater amounts without lowering the urinary pH too much.

Question 3

Net filtration pressure equation

Answer 3

(Capillary hydrostatic pressure - Interstitial hydrostatic pressure) - (Capillary oncotic pressure - Interstitial oncotic pressure)

Question 4

Describe the relationship b/w GFR and serum creatinine concentration.

Answer 4

The relationship b/w GFR and serum creatinine is NONLINEAR. As long as GFR is w/in normal range, serum creatinine levels rise only in small increments. When GFR reaches below 60 mL/min, even small decreases in GFR will result in large increases in serum creatinine. (“Every time GFR halves, serum creatinine doubles”)

Question 5

Excretion rate equation

Answer 5

Excretion rate = Filtered - Reabsorbed [(GFR)(Plasma conc. of x) - (Reabsorption of x)]
OR (Urine conc. of x) (urine flow)