Term
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Definition
| limited secretory mechanism that secretes substances from peritubular capillary to tubular fluid |
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Term
| Examples of organic anions |
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Definition
Antibiotics
Diuretics
Antiviral drugs
Cytostatics
Endogenous metabolites |
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Term
Describe the specificity and transport rate for Organic anions in the proximal tubule
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Definition
low specificity and maximum transport rate
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Term
Proteins that are known to deal with organic anions
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Definition
organic anion transporters
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Term
How many OA--alpha ketoglutarate antiporter mechanisms are there?
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Definition
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Term
| How is the alpha-ketolutarate brought into the cell? |
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Definition
sodium potassium ATP-ase in the basolateral membrane lowers Na+
Na+ dicarboxylate transporter (NaDC) brings alpha-ketoglutarate into cell |
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Term
| How do OA-s leave the cell? |
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Definition
| Cross the apical membrane with MRP2 or OAT4 |
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Term
| What dru can inhibit organic anion secretion? |
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Definition
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Term
Describe the specificity and transport rate for the organic cations
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Definition
Low specificity and maximum transport rate
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Term
Examples of organic cations
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Definition
Cratinine
Dopamine
Epinephrine
Norepinephrine
Atropine
Isoproteerenol
Cimetidine
Morphine
Quinine
Amiloride
Procainamide |
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Term
| What are the four transport pathways for OC+'s to enter the cell? |
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Definition
passive diffusion
OCT (1,2,3)
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Term
| What drives the uptake of organic cations against their chemical concentration gradient? |
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Definition
cel-negative potential difference
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Term
How do organic cations leave the cell? (cross the apical membrane)
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Definition
Two OC+-H+ antiporters
MDR1 |
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Term
What does it mean that some organic cations are filterable at the renal corpuscle while others are extensively bound to plasma proteins?
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Definition
Filterable at renal corpuscle- amt secreted is added to the amt filtered
Bound to plasma proteins- limited filtration so secretion is only mechanism for excretion |
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Term
Give an example of an organic anion secreted by the OAT pathway
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Definition
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Term
| Why is PAH used for mesurement of effective renal flow? |
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Definition
PAH is not reabsorbed so-
Excreted load= filtered load + secreted load
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Term
| What happens as PPAH increases an begins to approach TMPAH? |
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Definition
| PAH starts to appear in renal vein>Less plasma is cleared of PAH>volume of plasma cleaned per minute(CPAH) decreases |
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Term
Above TM what accounts for the major portion of PAH in urine?
Below TM what accounts for the major portion of PAH in urine? |
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Definition
Above- filtration
Below- tubular secretion |
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Term
| Why does CPAH approach CIN? |
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Definition
| PPAH get larger so the fraction of PAH secreted gets smaller |
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Term
| In reality about how much of the PAH does he kidney remove from the plasma? |
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Definition
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Term
| How can the actual renal flow be obatained? |
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Definition
| dividing the effective renal plasma flow (ERPF) by the extraction ratio for PAH |
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Term
| What is the extraction ratio? |
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Definition
| the fraction of a substance which is removed from the plasma by the kidneys |
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Term
A small V indicate a larger____?
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Definition
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Term
| What is an example of an organic anion that undergoes both active reabsorption and active secretion? |
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Definition
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Term
If urate only represents 5% of total urinary nitrogen what is the bulk of it excreted as?
Where does the nitrogen come from? |
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Definition
Urea
Derived from metabolism of ingested and endogenous proteins. |
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Term
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Definition
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Term
| How much urate is reabsorbed in the proximal tubule? |
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Definition
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Term
| What sort of transport does urate undergo? |
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Definition
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Term
| What is predominantly he net urate flux? |
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Definition
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Term
| What four factors could play a role in production of hyperuricemia in gout? |
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Definition
Dec filtration rate with maintained reabsroption rate
increased reabsorption of urate
decreased secretion of urate
increased production of urate |
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Term
| When do principal cells not dominate the overall transport of K+? |
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Definition
when aldosterone is inhibited.
(what would inhibit aldosterone- diuretics) |
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Term
Is it active, passive, or both types of K+ transport in the proximal tubule?
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Definition
Both types
bu most reabsorption in PT is passive |
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Term
What sort of K+ reabsorption occurs in the distal tubule?
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Definition
| active, passive, and cell specific |
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Term
| How do K+ concentration, the flow rate of the tubule, and electrical gradient all contribute determining K+ secretion? |
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Definition
-secretion increases when ICF K+ is high or TF K+ is low
- increased flow causes TF K+ to be lowered which reseults in increased secretion
-reabsorption of Na+ or poor reabsorption of anions can change the electrical gradient and promote secretion |
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Term
What effect does aldosterone have on K+ and Na+?
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Definition
| stimulates the secretion of potassium and the reabsorption of sodium |
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Term
| Three parts of hypermineralocorticoidism |
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Definition
hypertension
hypokalemia
metabolic alkalosis |
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Term
| What is the acute result of acute acidosis? |
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Definition
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Term
| What is the result of chromic acidosis on potassium? |
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Definition
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Term
| Why can weak organic acids and bases undergo passive reabsorption and/or secretion? |
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Definition
| the nonionized form i non-polar and lipid soluble |
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Term
Describe the effect of acidosis and alkalosis on weak acids.
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Definition
Acidosis- excretion of organic anions decreases because they are reabsorbed into the peritubular fluid
Alkalosis- excretion increases because weak acids ionize abd become less permeable |
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Term
Describe the effects of acidosis and alkalosis on weak bases.
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Definition
Acidosis- (normal urine)- weak bases are charged and excreted
Alkalosis- weak bases are uncharged and soluble - therefore charged and excreted |
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