Renal Hemodynamics- Weber Flashcards

1
Q

kidney functions to ______ metabolic waste products, foreign chemicals, drugs, and hormone metabolites

A

excrete

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2
Q

kidneys______ water and electrolyte balance (by increasing excretion or reabsorption)

A

regulate

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3
Q

what happens if Na+ intake increases

A

kidney compensates by excreting what we have in excess

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4
Q

the kidneys regulate arterial pressure by stimulating what system

A

RAAS

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5
Q

kidneys regulate what balance by excreting HCO3- if pH goes above 7.4

A

acid-base balance

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6
Q

what 3 things does the kidney help synthesize

A

erythrocytes
vitamin D (active form)
glucose

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7
Q

most important function of kidneys

A

filtering the plasma

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8
Q

what is so important about filtering the plasma

A

get the waste products out of blood

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9
Q

kidney filters the plasma and then does what

A

puts the filtered plasma back into blood

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10
Q

severe abnormalities of body fluid volumes and composition occur in this patient

A

patient with chronic kidney disease or acute kidney failure

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11
Q

if you see patient with abnormal ion concentrations and body fluid volumes what are you thinking

A

kidney disease

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12
Q

_____% of what is filtered in bowman’s capsule gets picked up by what

A

60-70%; peritubular capillaries

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13
Q

nephrons are coupled w/ what

A

renal vasculature

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14
Q

3 main kidney processes

A

glomerular filtration
tubular reabsorption
tubular secretion

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15
Q

net effect of 3 main kidney processes

A

excretion

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16
Q

what do we see in urine

A

what was removed from the blood

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17
Q

site where tubular reabsorption mainly happens

A

PCT

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18
Q

site where tubular secretion mainly happens

A

DCT and collecting duct

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19
Q

baroreceptors of the kidney

A

JG cells

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20
Q

what part of renal corpuscle allows us to maintain high pressure and create ultrafiltrate

A

fenestrated endothelium of capillaries

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21
Q

sense solute delivery (what gets moved into glomerular capillaries)

A

macula densa

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22
Q

___% of plasma that enters glomerulus is filtered

A

20%

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23
Q

____% of plasma that enters glomerulus is not filtered and leaves through efferent arteriole

A

80%

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24
Q

general cardiac output of body in liters

A

5L

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25
Q

___% of perfusion of whole system goes to the kidneys

A

20%

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26
Q

normal GFR

A

125 ml/min

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27
Q

why is the control of GFR so important?

A

b/c our entire plasma volume is filtered 60X per day

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28
Q

what 2 things influence how things are filtered:

A
  1. particle size
  2. charge
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29
Q

smaller particles like water, Na+, and glucose are freely or not freely filtered

A

freely filtered (1.0)

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30
Q

one of the key components of generating oncotic pressure

A

albumin (protein)

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31
Q

not freely filtered (good b/c want to keep this in vascular space)

A

albumin

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32
Q

presence of protein in urine sample means what

A

something is wrong

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33
Q

GBM has negative charge, so what molecule is negatively charged and kept from being filtered

A

albumin (protein)

34
Q

if Jv is positive, what happens

A

fluid is moving out of capillary

35
Q

if Jv is negative what happens

A

fluid is moved into capillary

36
Q

Kf (filtration coefficient) depends on what

A

of opened capillaries

37
Q

Pc (capillary hydrostatic pressure) depends on what

A

MAP and arterial resistance; MVP and venous resistance

38
Q

Pif (interstitium hydrostatic pressure) depends on what

A

interstitial fluid volume (lymphatic fluid reabsorption)

39
Q

changes with what

A

endothelial permeability

40
Q

depends on what

A

plasma protein concentration

41
Q

depends on what

A

interstitial protein concentration

42
Q
A

GFR

43
Q
A

Pgc= glomerular capillary hydrostatic pressure
Pbs= bowman’s space hydrostatic pressure

44
Q
A

oncotic capillary pressure

45
Q
A

bowman’s space oncotic pressure

46
Q

under normal conditions, no protein is filtered into urine so what should be 0

A
47
Q

4 main things that affect GFR

A
  1. Kf
  2. hydrostatic pressure in glomerular capillaries
  3. hydrostatic pressure in bowman’s space
  4. oncotic pressure in glomerular capillaries
48
Q

what does this depend on

A

plasma protein concentration

49
Q

if GFR is positive, fluid movement is where

A

out of capillary

50
Q

Decrease number of functional glomerular capillaries
Thickening of glomerular capillary membranes
Chronic unmanaged HTN or diabetes mellitus (decrease renal function)

A

will affect Kf

51
Q

downstream blockage such as a kidney stone or ureter blockage causes increase in upstream pressure where

A

hydrostatic pressure in bowman’s space (Pbs)

52
Q

this pressure is typically constant b/c protein stays in capillary, but can be altered during extreme starvation

A

oncotic pressure

53
Q

what stays fairly constant between afferent and efferent arterioles

A

hydrostatic pressure (Pgc)

54
Q

what significantly decreases from afferent to efferent arteriole

A

ultrafiltration rate

55
Q

why does oncotic pressure increase when you move through glomerular capillaries?

A

concentration of protein increases

56
Q

important in controlling filtration and is the primary driver in maintaining GFR

A

Pgc (hydrostatic pressure from glomerular capillaries)

57
Q
A
58
Q

resistance regulated where

A

arterioles

59
Q

lower pressure at end of efferent arteriole why

A

because blood is going through peritubular capillaries and back into renal vein to system; so matches pressure of other capillaries

60
Q

normal pressure through capillaries

A

25 mmHg

61
Q

high mmHg seen in afferent arteriole

A

60 mmHg

62
Q

2 main things that regulate Pgc (hydrostatic pressure of glomerular capillaries)

A
  1. MAP
  2. arteriole resistance
63
Q

increase in MAP, increases blood flow into kidneys=

A

increase in Pgc, net filtration pressure and GFR

64
Q

increase resistance of afferent arteriole=

A

decrease in GFR

65
Q

what regulates renal blood flow

A

arteriole diameter

66
Q

RBF =

A

pressure/resistance

67
Q

resistance is set by balance of what

A

vasoconstrictors and vasodilators

68
Q

activates a1 receptors (vasoconstriction)

A

SNS and catecholamines

69
Q

vasoconstrictor and decreases RBF

A

Ang II

70
Q

potent vasoconstrictor released in response to endothelial damage

A

endothelin

71
Q

causes dilation of afferent arterioles and constriction of efferent arterioles (increase GFR)

A

ANP

72
Q

vasodilation of both afferent and efferent arterioles; protective for RBF when Ang II is increased

A

prostaglandins

73
Q

vasodilation of renal arterioles and treats hemorrhage

A

dopamine

74
Q

maintains vasodilation of kidneys

A

NO

75
Q

2 main ways RBF is autoregulated

A

myogenic regulation
tubuloglomerular feedback

76
Q

describe autoregulation of RBF (myogenic regulation)

A

increase in arterial pressure, stretch, and then vasoconstrict

77
Q

JG cells sense afferent arteriole pressure
macula densa cells sense NaCl delivery
renin release and RAAS as appropriate

A

tubuloglomerular feedback

78
Q

if there is an increase in solute delivery sensed by macula densa, what does that mean for GFR

A

it is increased

79
Q

is tubuloglomerular feedback response positive or negative feedback

A

negative

80
Q

response to low GFR (5 things)

A
  1. JG cells sense decrease in perfusion pressure
  2. renin release
  3. RAAS activated
  4. increase in bp and volume
  5. homeostasis restored
81
Q

Of what we filter through glomerular capillaries, we absorb about _____% into peritubular capillaries

A

70%

82
Q

Jv is always _______ in peritubular capillaries

A

negative (reabsorption)