Physiology 4 + 5 Flashcards

1
Q

what is the normal GFR in litres per day?

A

180

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2
Q

kidneys reabsorb creatinine T or F

A

F

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3
Q

of reabsorption and filtration, which is specific?

A

reabsorption

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4
Q

where is most filtered fluid reabsorbed in the nephron?

A

proximal tubule (about 80ml/min)

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5
Q

give examples of substances secreted from the proximal tubule

A
Ach
adrenaline
noradrenaline
drugs
H+
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6
Q

what substanes are reabsorbed by the proximal tubule?

A
sugars
amino acids
phosphate
sulfate
lactate
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7
Q

epithelial cells are polarised T or F

A

T

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8
Q

what membrane does a substance have to cross to get from the tubular lumen to the tubular epithelial cells?

A

apical membrane

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9
Q

what does paracellular reabsorption mean?

A

substance is reabsorbed through tight junctions between epithelial cells

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10
Q

what does transcellular reabsorption mean?

A

substance is reabsorbed through the epithelial cell itself

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11
Q

how does secondary active transport differ from primary?

A

carrier molecule is transported coupled to the concentration of an ion eg Na (rather than just moving against its own conc gradient)

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12
Q

how much filtered salt is reabsorbed within the proximal tubule?

A

about 2/3

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13
Q

which ion leaves the cell in the Na/K pump?

A

Na

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14
Q

how is sodium conc in the ECF kept higher than the ICF?

A

any Na that makes it into the cell is forced to leave by the Na/K pump

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15
Q

Na leaves the epithelial cells by what route?

A

transcellular

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16
Q

Cl and H20 leave the epithelial cells by what route? why are they reabsorbed?

A

paracellular; an osmotic and electrochemical gradient are created by the movement of Na into the blood

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17
Q

plasma proteins are more concentrated in the proximal tubule than in the afferent arteriole: T or F

A

T (glomerular filtration decreased volume of fluid so more proteins in a smaller vol)

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18
Q

how is the osmolarity of the tubular fluid kept unchanged?

A

reabsorbing water and salt in equal proportions

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19
Q

reabsorption of glucose happens where?

A

proximal tubule

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20
Q

Na/K pump is located in what membrane?

A

basolateral membrane

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21
Q

Na/glucose transporter is located in what membrane?

A

apical membrane

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22
Q

rate of filtration is equal to…

A

plasma conc x GFR

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23
Q

kidneys filter most glucose at low glucose concentrations T or F

A

F, filter at high glucose concs

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24
Q

if kidneys still filter a substance when reabsorption stops, what happens?

A

it is excreted as urine

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25
Q

does reabsorption have a limit?

A

yes, when the transport mechanisms become saturated

26
Q

what kidney functions will appear as an exponential line that plateaus?

A

reabsorption mainly

secretion

27
Q

the tubular fluid is ___ when it leaves the proximal tubule

A

iso-osmotic

28
Q

what does iso-osmotic mean in terms of the proximal tubule

A

it has the same osmolarity as the plasma (300mosmol/l)

29
Q

main function of the loop of henle?

A

generate a cortico-medullary solute concentration gradient

30
Q

the cortico-medullary solute conc gradient will form what tonicity of urine?

A

hypertonic urine

31
Q

the tubular fluid in the medulla has a higher osmolarity than in the cortex T or F?

A

T

32
Q

what is countercurrent flow?

A

fluid moving down the descending limb as well as fluid moving up the ascending limb

33
Q

what type of nephron has longer loops of henle?

A

juxtamedullary nephrons

34
Q

cells of the ___ limb are very permeable to water but do not reabsorb salt

A

descending

35
Q

cells of the ___ limb are very permeable to salt but impermeable to water

A

ascending

36
Q

at what parts of the ascending limb is reabsorption carried out via active transport/diffusion

A

diffusion at the thin lower end of the limb

active transport at the thick, upper part of limb

37
Q

what kind of fluid bathes the wall of the tubule?

A

interstitial fluid

38
Q

TALH triple cotransporter pumps ions ___ ___ the lumen

A

out of

39
Q

where are Na and Cl reabsorbed in the loop of henle?

A

its thick upper part of the ascending limb

40
Q

what group of drugs can block the triple co-transporter?

A

loop diuretics

41
Q

the triple co-transporter is located in what membrane?

A

apical membrane

42
Q

how does chloride get into and out of the epithelial cells of the loop of henle?

A

in via triple co-transporter

out via potassium/cl transporter

43
Q

what type of ion undergoes “recycling” to get in and out of the loop of henle?

A

K+

44
Q

taking salt away from the tubular fluid will have what effect on its osmolarity?

A

will decrease it to 200 (was 300mosmol/l)

45
Q

when salt is reabsorbed in the ascending loop of henle, where does it go? what effect will it have on this substance’s osmolarity?

A

into the intersitial fluid (will increase its osmolarity to 400mosmol/l)

46
Q

why does the descending limb’s osmolarity increase during reabsorption of salt?

A

water leaves this area by osmosis to dilute the now concentrated interstitial fluid (desc limb’s tubular fluid now becomes concentrated)

47
Q

when is steady state said to have been reached

A

when tubular fluid of the ascending limb is 100mosmol/l

48
Q

what tonicity of fluid is in the proximal tubule?

A

iso-osmotic

49
Q

what tonicity of fluid is in the ascending limb?

A

hypotonic aka hypoosmotic

50
Q

how much urea is reabsorbed back into the blood?

A

50%

51
Q

what 2 substances set up the corticomedullary conc gradient?

A

salt

urea

52
Q

what does countercurrent multiplication do?

A

concentrate the medullary intersitial fluid

53
Q

why do we need the corticomedullary conc gradient?

A

allows you to produce urine of different volumes and concentrations

54
Q

if you have a high content of vasopressin/ADH in the blood, are you hydrated or dehydrated?

A

dehydrated

55
Q

blood osmolarity ___ as it dips down into the medulla

A

rises (more salt gained)

56
Q

blood osmolarity ___ as it rises into the cortex

A

falls (more water gained)

57
Q

osmolarity increases as the level of ___ increases

A

salt

58
Q

there is no net change of osmolarity in the blood coming into and leaving the vasa recta: T or F

A

T

59
Q

vasa recta capillaries are impermeable to NaCl and water T or F

A

F, are considered “leaky” so are permeable

60
Q

main job of the vasa recta?

A

keeps the corticomedullary conc gradient in place