Tubular transport Flashcards
kidneys filter about ____ L of water every day and _____ of Na per day
180 L of water and 25000 of Na
Solutes that move with water reabsorbed by a paracellular route are taken up by ___________
“solvent drag”
Reabsorption is _________ since reabsorption of water follows uptake of solutes closely at PCT
iso-osmotic
Primary driving force for transport in the PCT is the __________ (present in the basolateral membrane) which has a 3Na+/2K+ stoichiometry
(Na+,K+)-ATPase
Na+ crosses lumenal membrane in PCT via________
Na+/H+ antiporter
Low cytoplasmic Na+ drives uptake of sugars and amino acids across lumenal membrane in PCT via __________
Na+-coupled cotransporters
Cl- diffusion in PCT causes _________________ that drives paracellular Na+ uptake
lumenal positive transepithelial potential
glucose threshold for reabsorption
<200 mg/dl
splay?
some glucose escapes uptake
Loop of Henle reabsorbs of ____ Na+ and Cl- and ____ of water
25% and 23%
Na+, K+ and Cl- are taken up together vi a ________ in the lumenal membrane of loop of henle
Na+/K+/2Cl- co-transporter
Distal tubule and collecting duct account for reabsorption of ___ of filtered Na+ and Cl-
7%
_____ ADH —> high water permeability —> extensive reabsorption of water —> concentrated urine
high
Na+ and Cl- reabsorbed via ________ in the DT
Na+/Cl- cotransporter
what is defective in gitelman’s syndrome
Na+/Cl- con-transporter in DT
thiazide diuretics acts on
Na+/Cl- con-transporter in DT
Bartter’s syndrome what is wrong and what is it characterized by
- Na+/K+/2Cl- co-transporter is defective and it is characterized by hypokalemia
loop diuretics like furosemide inhibits
Na+/K+/2Cl- co-transporter in loop
Principal cells in CT absorb Na+ via apical ________
Na+ channels
liddle’s syndrome
mutation in Na+ channel in CT leading to an increase in Na+ reabsoprtion and thus increased blood pressure
amiloride
inhibits the Na+ channel in the CT
Cl- reabsoprtion in CT occurs by
paracellular
which cells contain ADH sensitive water channels
principal cells
diabetes insipidus
no ADH ressponse
High water intake —>excretion of a _____ urine
High water intake —>excretion of a dilute urine (as low as 50 mOsm/L
Must excrete about _____ mOsm of solutes per day (50% urea)
600
Since maximum osmolality of urine is 1200 mOsm, minimum urine volume is about ____ L
0.5
characterized by the appearance of glucose in the urine
diabetes mellitus
resulting in excretion of excessive water
diabetes insipidus
which segment of the renal tubule is there no transepithelial potential difference
distal tubule
