renal 3 - reabsorbtion & secretion

Question 1

how much fluid is filtered per day? how much of that is excreted?

Answer 1

180L/day but only 1% (1.5L) is excreted

Question 2

why do we filter so much per day? (2)

Answer 2

to rapidly filter foreign substances
to rapidly regulate ions and water

Question 3

What drives reabsorbtion at the proximal tubul?

Answer 3

Na+

Question 4

what is the apical side?

Answer 4

faces the tubule lumen

Question 5

what side does basolateral face

Answer 5

extracellular fluid

Question 6

transepitheilial transport

Answer 6

substances cross the apical and basolateral membranes of the tubule cells to enter into the ECF

Question 7

paracellular transport

Answer 7

susbstances pass through the cell to cell junctions between two adjacent tubule cells

Question 8

where is active transport found most

Answer 8

Basilateral side and is always active via Na-K-ATPase

keeps Na concentration low in tubule cell, high outdside

Question 9

how is secondary active transport used in proximal tubule cells?

Answer 9

secondary active transport: smport with Na+

glucose moves in symport with Na+

Question 10

Passive reabsorbtion

Answer 10

e.g urea nitrogenous waste product

Question 11

what is urea?

Answer 11

nitrogenous waste product from protein break down

Question 12

Receptor mediated endocytosis

Answer 12

megalin can bind to proteins & peptides that allow transport via endocytosis. then is digested by lysosmes. (very small amounts of protiens in pee cuz it gets reabsorbed)

Question 13

Saturation:

Answer 13

the max rate of transport that occurs when all available carriers are occupied (never reach this) TRANSPORT MAXIMUM

Question 14

If too much glucose filtration exceeds how much you can reabsorb, what will happen?

Answer 14

it will not be reabsorbed since you dont have enough to move it. It will exit in your pee (like diabetes sweeter pee) *called glucosuria

Question 15

what is the cacluation for excretion

Answer 15

excretion = filtration - reabsorbtion + amount secreted

Question 16

how do peritubular capillary pressures favor reabsorbtion?

Answer 16

excess plasma protiens draw fulids back into the peritubular capillary. its called osmotic pressure

Question 17

what is secretion

Answer 17

the transfer of molecules from the extracuelluar fluid into the lumen of the nephron

Question 18

give an example of secretion of organic solutes, which use (tertiary) active transport

Answer 18

-organic anion transporters: broad range of prodcts transported

Question 19

aKG-:

Answer 19

a-ketoglutarate is a by-product of the citric acid cycle

Question 20

what are the steps in secretion?

Answer 20

1 direct active transport
2 secondary indirect active transport
3 tertiary indirect active transfort
4 organic anions enter lumen in exchange for dicarboxylate

Question 21

what is an OAT trasporter?

Answer 21

uses energy from transporting dicarboxylates down its concentration gradient to move OA- against its concentraion gradient

Question 22

What is a competitor? what does it have to do with penicillin excretion?

Answer 22

penicilin would be excreted within 3-4 hrs

probenecid is a competitor which is preferentially secreed by the OAT transported, allowing penicillin to stay in the body