Misc Kidney Physiology Flashcards
What are the 4 functions that can give an indication of Kidney Function ?
- GFR
- Plasma Clearance of Solutes
- Renal Blood Flow
Why is Inulin useful in ascessing kidney function ?
It is not produced by the body, metabolized by the body. It is excreted by the kidney. It is not reabsorbed or secreted.
How do you calculate GFR ?
UF x Uin / Pin
- UF is urine flow
- Uin is urine inulin
- Pin is plasma inulin
What is clearance ?
The volume of plasma cleared of a substance per unit time
If clearance of a substance is less than GFR what does that mean ?
The substance is reabsorbed
If clearance is greater than GFR what does that mean ?
The substance is secreted.
What is the extraction ratio ?
The fraction of substance removed from the plasma.
Plasma Inulin =
Rate of Infusion / Rate of Output
Filtration Rate =
GFR x Px
Excretion Rate =
UF x Ux
What are the 4 routes substances move in the kidney ?
Vein, Artery, Ureter, Lymph
Is NaCl produced in the body ?
Is Urea Ingested ?
No- you only have to worry about ingestion and excretion
No you only have to worry about production and excretion.
What is mass flow ?
It expresses solute movements as a function of time.
What is the extraction ratio of X ?
Ax - Vx [renal venous] / Ax
What will reabsorption do to the extraction ratio ?
It will lower it
What will secretion do to the extraction ratio ?
It will raise it .
What do you use to measure renal plasma flow ?
Para amino hippuric acid
What is the clearance rate of Creatine ?
140 ml per min
How much creatine does the body make a day ?
2 g
How do you calculate the renal plasma flow ?
C (pah) / Extraction Ratio
How do you get renal blood flow from renal plasma flow ?
You get renal blood flow by dividing the plasma flow by ( 1 - hemacrit )
What is the plasma flow of PAH ?
0.9 - 0.95
What is C pah ?
It is a measure of effective renal plasma flow.
Cpah = (UF c Upah) / Ppah
