Renal 3 Flashcards
Regulated reabsorption allows kidneys to…
selectively return ions and water to the plasma to maintain homeostasis
Filtrate in lumen and ECF initially have…
similar solutions conc.
Most renal transport is…
transcellular
______ transport is used to generate electrochemical, osmotic and concentration gradients for reabsorption
active
Na+ is pumped out of the basolateral side of the cells by Na+K+-ATPase through active transport to…
prevent build up
Secondary active transport of Na+
symport with glucose, amino acids, other organic metabolites
How are urea nitrogenous waste products reabsorbed?
passive transport
What is reabsorbed through endocytosis?
very small plasma proteins or peptides
megalin
receptor binding plasma proteins that mediate endocytosis
saturation
The max. rate of transport that occurs when all available carriers are occupied
The majority of substances transported in the nephron use…
membrane proteins
transport maximum
the transport rate at saturation
The amount of glucose filtered depends on..
the plasma glucose conc.
Reabsorption of glucose is proportional to..
plasma conc. until transport max is reached
renal threshold
the plasma conc. of a solute when it first begins to appear in urine
renal threshold occurs at…
transport max
glycosuria or glycosuria
- glucose appearing in urine
- occurs with elevated blood glucose
- rare genetic disorder with reduced transporters
secretion
transfer of molecules from the ECF into the lumen of the nephron
organic anion transporters
tertiary active transport; broad range of products transported
alpha-hetoglutarate (aKG)
by-product of the citric acid cycle
probenecid
preferentially secret by the OAT transporter so it was given with penicillin to allow penicillin to stay in the body longer
excretion=
filtration-reabsorption+secretion
How do we directly look at filtration, reabsorption and secretion at the level of an individual nephron?
experimentally and analysis of urine and blood
clearance
rate at which solute disappears from the body by excretion or metabolisms; noninvasive way to measure GFR
clearance of X =
(mg/min)/(mg/mL)
To most accurately calculate GFR we need to look at the clearance of…
a substance that is freely filtered and neither reabsorbed or secreted
creatinine
commonly used to measure GFR and indicator of renal function
net reabsorption
If filtration is greater than excretion
net secretion
If excretion is greater than filtration
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