Renal Phys--> Renal basics Flashcards
What percent of CO usually goes through kidneys?
20%
- about 1000ml/min
What percent of the 1000ml/min is plasma and cell parts?
600ml is plasma
400 is cell parts like RBCs
What is the 600ml called?
Renal plasma flow
What is unique of the glomerulus in terms of vasculature?
Artery to artery flow
What is normal size of fenestrations of the glomerulus? Should this fit RBC’s?
70-100nm
No because RBCs are usually 6-8um
Are podocytes charged? Effect?
Yes negatively
- now two opposing factors for albumin secretion. To big and hard to go against neg charge
What is the normal size of Na, K and CL in terms of daltons? Normal daltons filtered and completely excluded?
Na- 25d
K- 39d
Cl- 113d
7,000 d freely filtered
70,000 completely excluded (albumin 66,000d)
What is glomerular filtration rate?
The movement of fluid and solute across from capillary lumen into Bowman’s space across ALL glomeruli in both kidneys
What determines GFR and whats is its equation?
hydrostatic pressure and oncotic pressure
GFR= K(Pc+πif)- (Pif+πc)
What is a normal GFR?
180liters/day
125ml/min
right around 20% of renal plasma flow of 600ml
What is linear with the renal plasma flow then?
GFR
- if RPF goes down then so does GFR
What is the excretion rate of sodium?
100 mEq/liter
What do AgII, NE and prostaglandins do to afferent and efferent capillaries?
AgII- Vasoconstricts afferent and efferent
Ne- Vasoconstricts afferent and efferent
Prostaglandin- vasodilates only afferent caps
What gets unregulated when AgII is unregulated?
Prostaglandins
- Keeps from vasocontricting the afferent arteriole. Basically acts against AgII so that addition of AgII isnt pointless.
What is indicated in a DM pt in terms of drugs to protect their kidneys?
ACE inhibitor
- Decreases tonic vasocontriction of efferent arteriole which decreases pressure in glomerulus and decreases GFR.
- DM pts can get kidney damage from hyperfiltration
- Indicated in HF pts too to decrease after load.
