Renal Basics Flashcards
9 jobs of the kidney:
- Filtration
- blood pressure
- Na+ homeostasis
- K+ homeostasis
- H2O homeastasis
- Bone/mineral – vit D, PO4, Ca2+
- Acid/Base
- RBC production and regulation (EPO)
- gluconeogenesis
% of CO that gets first pass renal flow?
20%
** ~1000 mL blood per min!!!
Normal RPF (renal plasma flow):
600 mL/min
or 60% of the 1000 mL total renal blood flow
**40% of blood is RBCs
3 structure that create the barrier between glomerular capilary lumen and Bowman’s space:
- capillary endothelium
- basement membrane
- podocytes
What is allowed to pass through glomerlular capillary endothelium?
anything except protein and cells
Aside from size, what affects passage through BM and podocyte slits?
charge
**negative charge make passage of negatively charged particle (ie. albumin) more difficult
Size cutoff for freely filtered plasma components?
= 7,000 D
Na- 23 D
K- 39 D
urea- 60 D
Creatinine- 113 D
Size cutoff for plasma components to be completely excluded from filtration?
> 70,000 D
albumin= 66,000 D (and is neg charged so normally does not filter)
Normal glomerular capillary pressure:
60 mmHg
Normal Bowman’s space pressure:
15 mmHg
Normal glomerular capillary oncotic pressure:
29 mmHg
Normal Bowman’s space oncotic pressure:
0 mmHg
Net ultrafiltration pressure=?
(glomerular cap pressure + Bowman’s space oncotic pressu [both favor filtration]) - (Bowman’s space pressure + glomerular capillary oncotic pressure [both favor absorption])
Normal: (60 + 0) - (15 + 29)= 16 mmHg
Normal GFR?
180 L/day
125 mL/min
normal plasma flow in Efferent artery (ml/min)?
475 mL/min
600 mL (afferent) - 125 mL filtered by glomeruli
