Tubular transport

Question 1

kidneys filter about ____ L of water every day and _____ of Na per day

Answer 1

180 L of water and 25000 of Na

Question 2

Solutes that move with water reabsorbed by a paracellular route are taken up by ___________

Answer 2

“solvent drag”

Question 3

Reabsorption is _________ since reabsorption of water follows uptake of solutes closely at PCT

Answer 3

iso-osmotic

Question 4

Primary driving force for transport in the PCT is the __________ (present in the basolateral membrane) which has a 3Na+/2K+ stoichiometry

Answer 4

(Na+,K+)-ATPase

Question 5

Na+ crosses lumenal membrane in PCT via________

Answer 5

Na+/H+ antiporter

Question 6

Low cytoplasmic Na+ drives uptake of sugars and amino acids across lumenal membrane in PCT via __________

Answer 6

Na+-coupled cotransporters

Question 7

Cl- diffusion in PCT causes _________________ that drives paracellular Na+ uptake

Answer 7

lumenal positive transepithelial potential

Question 8

glucose threshold for reabsorption

Answer 8

<200 mg/dl

Question 9

splay?

Answer 9

some glucose escapes uptake

Question 10

Loop of Henle reabsorbs of ____ Na+ and Cl- and ____ of water

Answer 10

25% and 23%

Question 11

Na+, K+ and Cl- are taken up together vi a ________ in the lumenal membrane of loop of henle

Answer 11

Na+/K+/2Cl- co-transporter

Question 12

Distal tubule and collecting duct account for reabsorption of ___ of filtered Na+ and Cl-

Answer 12

7%

Question 13

_____ ADH —> high water permeability —> extensive reabsorption of water —> concentrated urine

Answer 13

high

Question 14

Na+ and Cl- reabsorbed via ________ in the DT

Answer 14

Na+/Cl- cotransporter

Question 15

what is defective in gitelman’s syndrome

Answer 15

Na+/Cl- con-transporter in DT

Question 16

thiazide diuretics acts on

Answer 16

Na+/Cl- con-transporter in DT

Question 17

Bartter’s syndrome what is wrong and what is it characterized by

Answer 17

• Na+/K+/2Cl- co-transporter is defective and it is characterized by hypokalemia

Question 18

loop diuretics like furosemide inhibits

Answer 18

Na+/K+/2Cl- co-transporter in loop

Question 19

Principal cells in CT absorb Na+ via apical ________

Answer 19

Na+ channels

Question 20

liddle’s syndrome

Answer 20

mutation in Na+ channel in CT leading to an increase in Na+ reabsoprtion and thus increased blood pressure

Question 21

amiloride

Answer 21

inhibits the Na+ channel in the CT

Question 22

Cl- reabsoprtion in CT occurs by

Answer 22

paracellular

Question 23

which cells contain ADH sensitive water channels

Answer 23

principal cells

Question 24

diabetes insipidus

Answer 24

no ADH ressponse

Question 25

High water intake —>excretion of a _____ urine

Answer 25

High water intake —>excretion of a dilute urine (as low as 50 mOsm/L

Question 26

Must excrete about _____ mOsm of solutes per day (50% urea)

Answer 26

600

Question 27

Since maximum osmolality of urine is 1200 mOsm, minimum urine volume is about ____ L

Answer 27

0.5

Question 28

characterized by the appearance of glucose in the urine

Answer 28

diabetes mellitus

Question 29

resulting in excretion of excessive water

Answer 29

diabetes insipidus

Question 30

which segment of the renal tubule is there no transepithelial potential difference

Answer 30

distal tubule