Final Review Deck - Lecture V - Reabsorption and Secretion

Question 1

What membrane of the epithelial cell faces the lumen?

Answer 1

the apical membrane

Question 2

What membrane of the epithelial cell is on the opposite side of the lumen?

Answer 2

the basolateral membrane

Question 3

What are the peritubular capillaries doing more of?

Answer 3

reabsorption than secretion and filtration cause low bp

Question 4

What is the transcellular and paracellular path?

Answer 4

transcellular - goes through the cells
paracellular - goes through the junctions of two cells

Question 5

What does the sodium potassium pump drive?

Answer 5

the resorption of sodium - it is in the basolateral membrane

Question 6

What does the transprot of cations drive?

Answer 6

transport of anions through the transcellualr or paracellular pathway

Question 7

What does the transport of ions drive?

Answer 7

transport of water through transcellualr pathways or paracellular pathway

Question 8

What does the movement of water increase the concentration of in the lumen and cause them to move as well through the transceullar pathway?

Answer 8

potassium, calcium, urea

Question 9

Why is all bicrabonate absorbed?

Answer 9

cause it is a base - same with glucose need for energy

Question 10

How much urea is reabsorbed?

Answer 10

53% - can denature cells in the kidney

Question 11

In the proximal tubule what is most moving sodium across apical membrane?

Answer 11

sodium proton antiporter

Question 12

In the proximal tubule how does sodium move across the apical membrane?

Answer 12

Na + Pi symporter - parathyroid hormone increases renal excretion of phopshate by inhibiting this pump to prevent formation of calcium phosphate precipitates
Na + H+ antiporter
Na + Glu symporter

Question 13

In the proximal tubule how does sodium move across the basolateral membrane?

Answer 13

sodium potassium pump
3 bicarbonate out/ 1 sodium out
glucose always moves acorss

Question 14

What do protons do on the tubule lumen side?

Answer 14

combine with bicarbonate make carbonic acid and this become water and CO2 which diffuses to the epithelium and the ECF and in the epithelium CO2 combines with water and makes H+ and bicarbonate

Question 15

What causes the concentration of chloride to be higher in lumen?

Answer 15

due to cations and water leaving creating a gradient for chloride

Question 16

What happens to proteins that leak out of glomerular capillaries?

Answer 16

bind to receptors in the apical membrane in the proximal tubule and cause endocytosis and they are interalized as vesicles which will go to lysosomes and degrade them or be released back into the ecf via exocytosis

Question 17

What is the way H+ is secreted i the distal tubule and collecting duct?

Answer 17

not sodium dependent
-H+ ATPase which pumps out protons which come from dissociation of water
-H+/K+ ATPase
-K+ is reabsorbed through K+ channel

Question 18

What happens to the OH- that comes from dissociation of water?

Answer 18

combines with CO2 and makes bicarbonate which is reabsoirbed by bicarbinate chloride antiporter
-chloride which comes in from this is reabsribed back to ecf through chloride channel in basolateral membrane

Question 19

Since H+ in urine can make pH 4.5 how is it buffered?

Answer 19

-bicarbonate and makes co2 (reenters epithelial cell to make bicarbonate) and h20
-dibasic phopshate becomes monobasic phophate and sodium is reabsorbed
-ammonia becomes ammonium which cannot diffuse

Question 20

Where is most of the potassium reabsorbed?

Answer 20

proximal tubule

Question 21

Where is mot of the potassium secrted thorugh principal cells or reabsrobed by intercalated cells?

Answer 21

distal tubule

Question 22

Most of the what is happening to potassium in distal tubule?

Answer 22

it is being secrted by principal cells

Question 23

What is in the apical membrane distal tubule principle cells?

Answer 23

ROMK1 which is open at negative Vm and closes at depolarization and gets potassium in the kidney lumen - 3NA out and 2 K+ in so opem when hyperpolarized

Question 24

What happens if filtration greater than excretion?

Answer 24

reabsorption

Question 25

What happen if filtration less than excretion?

Answer 25

secretion

Question 26

If filtration and secretion are the same?

Answer 26

there is no net

Question 27