Renal: GFR Flashcards

1
Q

of all cardiac out put how much goes through both kidneys? each kidney?

A

of 5L, 1L in both kidneys, 500 ml in each (per min)

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2
Q

where are the inter vs intra lobular arteries

A

inter sits on top of the lobe, intra sits between the lobes

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3
Q

where is the arcuate artery

A

lies parallel on top of the lobe

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4
Q

where is the glomerulus

A

the bulbs on the ends of the afferent arterioles

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5
Q

where is the nephron

A

sticking out of the lobe, its head connects with the glomerulus

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6
Q

the afferent and effernt arterioles lead into where

A

the glomerular capillary that sits inside bowmans space

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7
Q

where does the glomerular capillary lie

A

inside bowmans space

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8
Q

what is PGC and what does it do

A

glomerular capillary pressure: pushes fluid from caps into bowmans space

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9
Q

what is PT and what does it do

A

tubular hydrostatic pressure: pushes fluid from bowmans space back into cap

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10
Q

what is oncotic pressure and what does it do

A

pressure from albumin, keeps water in the capillary space

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11
Q

what is the ultrafiltration coefficient and what does it do

A

the area available for filtration to occur (the permeability)

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12
Q

what is plasma flow

A

the continuous flow of plasma; the most important factor in the gfr

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13
Q

what happens to pressure of filtration as the glomerular cap length increases

A

ultrafiltration pressure decreases, because the long the glom cap, the lower the plasma flow at the bottom, the higher the albumin, the higher the oncotic pressure, the lower the pressure out

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14
Q

how to calculate single nephron gfr

A

permeability (kf) x ultrafiltration rate (ultrafiltration is hydrostatic pressure gradient - oncotic pressure gradient)

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15
Q

how does kf impact gfr

A

kf inc, gfr inc

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16
Q

how does ultrafiltration pressure impact gfr

A

uf inc, gfr inc

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17
Q

how does oncotic pressure impact gfr

A

onc inc, grf dec

18
Q

how does plasma flow impact gfr

A

plasma flow inc, gfr inc

19
Q

what is the most important determinant of gfr

A

plasma flow

20
Q

how much gets filter by the glomerulus per minute? per day

A

100 -120 ml/min, 150-170 L/day

21
Q

what determines renal blood flow

A

blood pressure (arterial), renal vascular pressure

22
Q

what happens to the afferent arteriole if bp falls vs rises? why?

A

falls, AA dilates: maintain renal blood flow
rises, AA constricts, to maintain normal renal blood flow

23
Q

the myogenic reflex in afferent arteriole does what

A

vasoconstricts and dilates the afferent arteriole

24
Q

what is tubuloglomerular feedback? is it myogenic?

A

its feedback from the tubules that alerts the afferent arterioles to constrict under cases where you have too much salt, and want to reduce the
GFR, it is not myogenic

25
Q

describe the tubuloglomerular feedback pathway

A

high na, adenosine released, causes AA contraction, more AA resistance, less plamsma flow, less GFR

26
Q

what happens when efferent arteriole has increased resistance

A

the macula densa cells can respond to sodium in the thick ascending limb and DCT. if there is too much, they’ll stimulate adenosine release.
adenosine causes muscular contractin in afferent arteriole
increased relasistance
less blood flow
less gfr

27
Q

what does angiotension 2 do to efferent arteriole

A

causes increases resistance in efferent to increase hydrostatic pressure and gfr

28
Q

qa gets impacted by the ____ arteriole. hydrostatic pressure gets impacted by the ____ arteriole

A

afferent, efferent

29
Q

what is convection

A

movement of small solute with bulk flow of water

30
Q

what solutes are freely filtered in the kidney ? why?

A

theyre small enough that they can go through, and provide the kidney with substrates to use

na, l, cl, glucose, bicarb, urea, creatinine

31
Q

why does the kidney need to be perm selective

A

so it doesnt lose the big molecules it needs

32
Q

is the glomerular cap more restrictive to neg or pos charged mols

A

negative

33
Q

how much macromolecule does a healthy person excrete

A

less than 10mg/24h

34
Q

why is gfr measured

A

to measure kidney fucntion

35
Q

how (generally) is gfr measured

A

using a freely filtered solute, so that solute clearance = gfr

36
Q

how does inulin measure gfr? what are the cons?

A

once inserted in, no resorption, but has to be given intravenously

37
Q

how does creatinine measure the gfr

A

free filtration, collect urine for 24h
creat clearance = urine flow rate x [urine creat]/[plasma creat]

38
Q

explain relationship between gfr and plasma creat

A

inversely prop

39
Q

what are healthy total protein and albumin measurements in the urine

A

<0.15g/24h, <30mg/24h

40
Q

describe what happens to protein in urine as diabetes develops. why?

A

too much protein in urine bc glom filtration doesnt work as well.