Renal Physl 9 Flashcards
What does excretion of substances depend on?
- Filtration rate
- Reabsorption
- Secretion
What can help estimate GFR?
The renal clearances of substances
What is Clearance?
The rate at which a substance is lost from the body by excretion or metabolism
What is clearance as described by an equation?
The volume of plasma cleared of a substance per minute
What is the equation of a clearance rate of substance in mL per minute?
The product of urine concentration of a substance and the urine flow rate. All divided by the plasma concentration of the substance
What is the clearance of substances that are only cleared by excretion?
The volume of plasma flowing through the kidneys that totally cleared of that substance in a certain period of time
What happens if inulin is injected intravenously?
Its freely filtered at the glomerular capillaries but its not reabsorbed or secreted
What clearance is equal to GFR?
The clearance of substances that are freely filtered but neither reabsorbed or secreted
What does a higher plasma conc of a substance do?
Increase the amount that is filtered
What does a high GFR mean?
More plasma is filtered at the glomerular capillaries so higher amounts enter the tubule
Why is creatinine not a perfect substance for GFR estimation?
Because a very small amount is also secreted into the tubules
