Kidney Function 2 Flashcards
which hormone controls water in kidney?
ADH/vasopressin
Calcium almost entirely absorbed where?
proximal tubule
what hormones control calcium in distal tubule? 2
parathyroid
vitamin D3
where is phosphate reabsorbed?
80-90% proximal tubule
Na+ absorbed where?
proximal tubule
glucose is 100% absorbed where?
proximal tubule
where are proteins and AAs reabsorbed?
proximal tubule
how much creatinine is reabsorbed?
None!
Urea comes from what? Loose gauge of what?
breakdown of proteins
gauge for renal function
3 layers of osmolarity in kidney are?
outer
inner
pila/deep
What’s so good about concentration increasing as you go deeper into kidney?
enables body to respond to diverse situations
water reabsorbed? 70% 20% 7% 3%
70% in proximal tubule
20% thin ascending loop
7% distal tubule
3% collecting duct
Na+ absorbed how and where?
active transport
proximal tubule
Na+ reabsorbed, what else follows? where? how?
anions: Cl- and bicarb
transcellular/paracellular space
via electrochemical gradient
‘tight’ junctions in proximal tubule are water tight?
Nope, pretty leaky to water, Na+,
Na+ absorbed and anions, what else? how? why?
H20
via osmotic gradient
50/50 transcellular/paracellular
H20 is absorbed in proximal tubules via osmotic gradient, what else is absorbed with it? 3 things
K+, Ca2+, urea because it’s dissolved in the H20 and diffuses
___% of O2 consumed by kidneys?
80%
electrochemical gradient in proximal tubule is how many mV?
-3mV
in the late proximal tubule, why do you get Na+ leaking back into lumen?
Bicarb get absorbed preferentially over Cl- as anions try to follow Na+ initially
So build up of Cl-, and it sucks out the Na+ at end of proximal tubule
at the end of distal proximal tubule there is a high concentration of what?
Na+ Cl-
What is reabsorbed in the thin ascending limb? how?
Na+ via passive diffusion through paracellular tight junctions
frusemide targets what? where?
Na+, K+ 2Cl- cotransporter in loop of henle
danger of frusemide?
Kypokalemia
water reabsorbed in thick ascending tubule?
Nope, tighter tight junctions
What happens to Na+ in thick ascending limb?
lots gets reabsorbed
50/50 paracellular/active transport
in Thick ascending limb what transporter is now in the baso-latreal border instead of Na/HCO3?
Cl/HCO3 which encourages Na+ to stay in and not leak back out
What happens to Na+ in distal convoluted tubule?
almost all gets reabsorbed via transcellular route
Where do thiazides work? why not as powerful as frusemide?
NaCl cotransporter block in distal convoluted tubule, not as powerful cause only affecting 5% of fluid
What is ENAC? where is it?
epithelial sodium channel in collecting duct passive sodium in
what happens to K+ in CD?
passive out into lumen
