Renal 3 (midterm 2)

Question 1

how much is filtered each day

Answer 1

180 L

Question 2

how much of the filtered stuff is actually excreted

Answer 2

1.5 L

Question 3

what does regular reabsorption allow kidneys to do

Answer 3

silently return ions to plasma to maintain homeostasis

Question 4

whats the reason fr lots of filtration but not much excretion

Answer 4

rapid way to remove unwanted materials

Question 5

what do solutes move through ?

Answer 5

nephron junctions

Question 6

what powers active transport

Answer 6

sodium

Question 7

what is transepithelial transport

Answer 7

substance crosses apical and basolateral membrane

Question 8

what is paracellular transport

Answer 8

substances pass through cell to cell junctions between two adjacent tubule cells

Question 9

where is Na transport always active via Na-K-ATPase

Answer 9

basolateral membrane

Question 10

what kind of transport does glucose/amino acid use to get into cell

Answer 10

secondary active transport with Na

Question 11

what kind of reabsorption does Urea do

Answer 11

passive

Question 12

what are the 2 other reabsorption methods

Answer 12

passive reabsorption
endocytosis

Question 13

what plasma proteins do receptor mediate endocytosis from lumen into epithelial cells

Answer 13

megalin

Question 14

the majority of substances transported in the nephron use _______ _________

Answer 14

membrane proteins

Question 15

define saturation

Answer 15

the maximum rate of transport that occurs when all available carriers are occupied

Question 16

can renal transport reach saturation

Answer 16

yes

Question 17

whats an example of saturation

Answer 17

glucose being completely reabsorbed in the proximal tubule

Question 18

what does the filtration of glucose depend on

Answer 18

the plasma [glucose]

Question 19

what is the transport maximum

Answer 19

the transport rate at saturation

Question 20

if saturation is occurring, some things may _________ completely

Answer 20

not reabsorb

see uncommon things in our urine

Question 21

what is renal threshold

Answer 21

the plasma concentration of solute when it first begins to appear in the urine

Question 22

when does renal threshold happen

Answer 22

at transport maximum

Question 23

___________ excretion is zero until the renal threshold is reached

Answer 23

glucose

Question 24

when something reached transport maximum, what starts happening

Answer 24

starts showing up in urine

Question 25

what is glucose appearing in urine called

Answer 25

glucosuria or glycosuria

Question 26

what capillary has a pressure that favours reabsorption

Answer 26

peritubular

Question 27

whats the net pressure to drive fluid and solutes from the interstitial space back into the capillaries at the peritubular capillaries

Answer 27

20 mm

Question 28

Which pressure drives the movement of a reabsorbed substance from the interstitial fluid into the peritubular capillary?

Answer 28

peritubular colloid osmostic pressure

Question 29

define secretion

Answer 29

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

Question 30

what does secretion mainly depend on

Answer 30

membrane proteins

Question 31

is secretion active or passive

Answer 31

active (against gradient)

Question 32

where does homeostatic regulation by secretion of K+ and H+ happen

Answer 32

distal tubule

Question 33

where does organic compound removal (medications, food additives) by secretion occur

Answer 33

proximal region

Question 34

what enhances the excretion of a substance

Answer 34

secretion

Question 35

what kind of secretion does organic solutes use

Answer 35

tertiary active transport

Question 36

what does a tertiary active transport mean

Answer 36

that the active transport process is 2 steps from the ATP

Question 37

what keeps the intracellular Na low

Answer 37

the Na-K-ATPase

Question 38

how do organic anions enter the lumen?

Answer 38

in exchange for a decarboxylate through an OAT4 transporter

Question 39

OAT transporter uses energy from what

Answer 39

transporting decarboxylates down its concentration gradient

Question 40

what is the story between penicillin and probenecid

Answer 40

penicillin was being excreted too fast so they competitively inhibited OAT transporters with probenecid so probenecid would be excreted instead of penicillin

Question 41

where are OAT transporters

Answer 41

both apical and basolateral membranes

Question 42

by the time fluid reaches the end of the nephron it bears __________ resemblance to the filtrate

Answer 42

little

Question 43

what is an indicator of overall kidney function

Answer 43

GFR

Question 44

what are the 2 things that are usually of clinical interest

Answer 44

renal handling GFR

Question 45

can excretion tell us details of renal function

Answer 45

no

Question 46

how do we directly look at filtration, reabsorption, and secretion at the level of an individual nephron

Answer 46

experimentally indirect methods using only analysis of urine and blood

Question 47

whats a non invasive way to measure GFR

Answer 47

clearance

Question 48

what is the clearance of a solute

Answer 48

the rate at which a solute disappears from the body by excretion or metabolism

Question 49

how is clearance measured for a solute that is cleared only by renal excretion

Answer 49

volume of plasma passing through the kidneys that has been totally cleared of that solute in a given period of time

Question 50

clearance for urea is 65 ml/min, what does this mean

Answer 50

the kidney removes all of the urea in 65 ml of plasma in one minute

Question 51

1 mg of solute Z in 100ml of plasma, you found 0.5 mg of Z appearing in urine /min

Answer 51

clearance of Z = 0.5 mg/min / 1mg/100ml = 50 ml/min