Renal- reabsorption, secretion, excretion Flashcards
where does the majority of reabsorption happen?
proximal tubule
what is the major cation in the extracellular environment?
Na+
how much sodium reabsorption occurs in the PCT?
2/3 (67%)
how much sodium is reabsorption occurs in the thick ascending limb?
25%
what molecules use the sodium gradient as secondary active transport into the PCT?
glucose
amino acids
phosphate, lactate, citrate
what molecule is antiported out of the PCT when Na+ is transported in?
H+
________ (+/-) oncotic pressure in the peritubular capillaries favors absorption of water
increased
how much glucose is typically reabsorbed?
100%
in diabetes, glucose transporters get __________ and glucose __________ (+/-) in urine
saturated
increases
glucose begins to appear in urine due to __________ slowing of reabsorption
gradual
if there is more glucose in the tubule, where will water go?
follow into the tubule
what is the triad of symptoms for diabetes?
polyuria
high glucose in urine
increased thirst
the thin descending limb is mainly permeable to what?
H2O
this part of the loop of henle is impermeable to water but permeable to solutes
thin ascending limb
this part of the loop of henle primarily is responsible for the reabsorption of Na+, Cl-, K+ and Ca2+
thick ascending limb
what transports Na+/K+/ and 2 Cl- out of the thick ascending limb?
sodium potassium chloride cotransporter
these are capillaries that form a U-shape with the tubules but the flow is in the opposite direction
vasa recta
function of the vasa recta
collect the reabsorbed water and solutes from the nephron tubules
water leaving the descending loop causes the nephron concentration to get ________
higher
solutes leaving the ascending loop causes the nephron concentration to get _______
lower
this is a diuretic that blocks the sodium/ potassium/ chloride cotransporter
furosemide
water leaving the descending loop enters the vasa recta and is brought _____
up
solutes leaving the ascending loop enter the vasa recta and are brought _____
down
can sodium be actively transported out of tubule cells into the interstitial space?
yes
how is Na+ transported out of the tubule cells into the interstitial space?
via aldosterone inserting more Na/K pumps
true or false: actively transporting sodium out of the tubule will reduce K+ levels
true
what causes the distal tubule to have variable permeability to water?
vasopressin (ADH)
how is Na+ reabsorbed into early distal tubule cells?
Na/Cl cotransporter
what kind of cells does aldosterone work on to increase the number of Na+ channels and Na/K ATPases in the DCT and the collecting duct?
principle cells
spironolactone is __________ sparing and blocks the action of _______
K+
aldosterone
where is K+ mainly reabsorbed?
PCT
some in the ascending limb as well
this cell in the DCT/ collecting duct is responsible for K+ reabsorption
intercalated cells
secretion of K+ in the DCT/ collecting duct occurs through this type of cell
principle cell
does cell lysis increase or decrease K+?
increase
effect of insulin on K+ levels
shifts K+ into cells
increases Na/K ATPase
effect of beta 2 agonists on K+ levels
shifts K+ into cells
effect of alpha adrenergic agonists on K+ levels
shifts K+ out of cells
H+ and K+ are exchanged in the _____ tubule
distal
where is urea mainly reabsorbed?
PCT
some in the collecting duct
where is urea mainly secreted
descending limb
effect of ADH on urea
increased reabsorption in the collecting duct
these two molecules increase in the blood when the kidney is no longer properly filtering
creatinine and BUN
what is the best/ most effective way to measure GFR
inulin
what is the most practical method of measuring GFR
creatinine
is creatinine reabsorbed?
no
is BUN reabsorbed?
yes
where is BUN made?
liver
this is a sugar that does no readily cross cell membranes, so it is not reabsorbed and is used as a short-term diuretic
mannitol
