Renal Flashcards

1
Q

Extracellular

A

Na
Cl
HCO3
Ca

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2
Q

Intracellular

A

K
Organic anions
Proteins
Mg

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3
Q

Protein (albumin) levels are highest in the _ and _ compartments

A

ICF

Vascular

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4
Q

Are membranes permeable to proteins

A

No

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5
Q

Oncotic (colloid osmotic) pressure

A

Pressure generated by large molecules (like proteins) in solution that are impermeable to membranes

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6
Q

How are ICF and ISF measured

A

Indirectly

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7
Q

ECF

A

Inulin, Na, thiosulfate

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8
Q

ICF

A

TBW-ECF=ICF

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9
Q

TBW

A

H2O

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10
Q

Plasma volume

A

I-albumin, Evans blue dye

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11
Q

Interstitial fluids

A

ECF-plasma=ISF

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12
Q

What drives ECF osmolality

A

Na and Cl

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13
Q

Na vasculature __ Na interstitial fluid ___ Na due to action of NaKATPase

A

> >

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14
Q

What causes increased ICF (Na)

A

Disrupted pump activity (hypoxia

Where Na goes water follows

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15
Q

ICF osmolality is driven by

A

K

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16
Q

ECF osmolality controls _ volume

A

ICF

Water enters of leaves ECF rapidly to balance osmolality of ECF and ICF

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17
Q

Osmotic equilibrium

A

Movement of water across cell membranes from higher to lower concentration as a result of osmotic pressure differences across that membrane

Osmotic presssure exerted across a membrane by a substance is also due to that membrane being impermeable to that substance

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18
Q

Mean forces tend to move fluid __

A

Outward

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19
Q

Total outward force

A

Plasma colloid osmotic pressure (28mmHg)

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20
Q

Total inward force

A

Outward (28.3)

Inward (28

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21
Q

What are the pressures

A

Mean capillary pressure (17.3)
Negative interstitial free fluid pressure (3)
Interstitial fluid colloid osmotic pressure (8)

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22
Q

How is ECF a reservoir

A

All water an solutes must pass through the ECF first

First calculate ECF then ICF

All solutes and water that enter or leave the body do so via ECF
ICF and ECF are in osmotic equilibrium
Equilibration occurs primarily by shifts of water, not solutes

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23
Q

Hypernatremia

A

> 146

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24
Q

Hyponatremia

A

<136

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25
Q

Hyper and hyponatremia is a __ problem

A

Water

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26
Q

What maintains the fluid distribution between plasma and ISF

A

Balance of hydrostatic and osmotic forces across capillaries

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27
Q

What determines ECF and ICF fluid distribution

A

Osmotic effect of small solutes across cell membranes

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28
Q

Isosmotic

A

Solutions that have the same osmolality as the ECF

When added to ECF, osmolality does not change , only the volume

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29
Q

Hyperosmotic

A

Osmolality greater than the ECF

When added to the ECF , osmolality increases and pulls water from the ICF into the ECF, resulting in an increase in ECF volume and a decrease in ICF volume

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30
Q

Hypoosmotic

A

Osmolality less than ECF

When added to ECF, osmolality decreases and water moved out of the ECF and into the ICF to equilibration. ECF and ICF volumes both increase

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31
Q

What give if want to dilute ECF and rehydrate cells

A

Hypotonic .45 salient

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32
Q

What administer if want to replace fluid loss and expand intravascular volume

A

Isotonic solution normal saline

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33
Q

What administer to treat severe hyponatremia

A

Hypertonic solution

3% saline

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34
Q

Prostagladins are protective of __

A

RBF

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35
Q

Prostagladins as buffers

A

Vasoconstriction effects of SNS/RAAS (the built in safety mechanism)

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36
Q

How do prostagladins with

A

Inhibits K channels in TAL, increasing Cl, impeding turnover of Na K 2 Cl channels, reducing NaCl reabsorption

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37
Q

NSAIDS and prostagladins

A

Interfere with PGE2 action, leading to Na retention

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38
Q

What kind of patient careful to give NSAIDS

A

Hypertensive patients, renal stenosis, patients on diuretics

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39
Q

Angiotensin II effect on RBF

A

Decrease

Decrease

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40
Q

ANP effect on RBF and GFR

A

Increase increase

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41
Q

Prostagladins effect on RBF and GFR

A

Increase increase

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42
Q

Sympathetic stimulation leads to what

A

Na K ATPase increase Na reabsorption at tubular epithelial cells

RAAS juxtaglomerular granular cells*mainly

Powerful vasoconstriction : afferent>efferent arteriole a1 adrenoceptors

INCREASED BP

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43
Q

Immediate effects of sympathetic stimulation

A

Stimulates renin secretion by the granular cells

Angiotensin II exerts thirst

Angiotensin II restores systemic blood pressure via vasoconstriction

Angiotensin II preferentially acts on efferent arteriolar

Stimulates Na reabsorption in PCT and DCT

GFR is stabilized

Systemic blood pressure is raised

44
Q

Eventually sympathetic stimulation

A

Decreased urinary output

Decreased urinary Na excretion

Increased water intake

45
Q

Acute Sympathetic activation effect on RBF, GFR, renin, Na reabsorption in proximal tubule

A

Ok

46
Q

Chronic effect of sympathetic activation RBF, GFR, renin, Na reabsorption in proximal tubule

A

Ok

47
Q
Afferent arteriole-vasodilation 
Prostagladins
Bradykinin
NO
Dopamine
ANP

RBF, GFR, peritubular capillary hydrostatic pressure

A

Increase increase increase

48
Q

Afferent arteriole vasoconstriction

RBF, gfr, peritubular capillary hydrostatic pressure

A

Decrease, decrease, decrease

49
Q

Efferent arteriole vasodilation

RBF, gfr, peritubular capillary hydrostatic pressure

A

Increase, decrease, increase

50
Q

Efferent arteriole vasoconstriction
Angiotensin II

RBF GFR peritubular capillary hydrostatic pressure

A

Decrease
Increase (sideways)
Decrease

51
Q

What promotes renin secretion

A

Renal sympathetic stimulation directly stimulate renin via B1 receptor activation in JG apparatus

Decrease NaCl delivery to the macula densa stimulates renin

Afferent arteriolar vasoconstriction leads to decreased pressure at the granular cells, which stimulates renin secretion

52
Q

What inhibits renin secretion

A

Increase Na and Cl reabsorption across the macula densa

Increased afferent arteriolar pressure

ADH

Angiotensin II(neg feedback)

53
Q

What does angiotensin II stimulate

A

Renal arteriolar constriction (efferent>afferent)

Na reabsorption in PT (via Na H exchanger)> TAL and CCD

Thirst

ADH secretion from posterior pituitary

Aldosterone secretion from adrenal cortex

54
Q

Angiotensin II causes what

A

Vasoconstriction, increased thirst, increased aldosterone secretion

55
Q

What does vasoconstriction lead to

A

Increased peripheral resistance and increase in systolic and diastolic bp

56
Q

What does increased thirst lead to

A

Increased water intake, increased blood volumes, increased CVP, increased CO and increase in systolic and diastolic blood pressure

57
Q

What does increase in aldosterone cause

A
Increased renal retention of salt and water
Increased in blood volume
Increase in CVP
Increase in CO
Increase in systolic blood pressure
58
Q

Angiotensin II preferentially ____ the efferent arteriole, but __ the afferent arteriolar

A

Vasoconstriction

Constricts

59
Q

Angiotensin II effect on arterioles

A

Increase afferent and efferent arteriolar resistance

Afferent

60
Q

What does increase afferent and efferent arteriolar resistsance cause

A

Decrease renal blood flow

Increased filtration fraction

Decreased capillary hydrostaticpressure

61
Q

What does increased filtration fraction lead to

A

Increased peritubular capillary colloid osmotic pressure

62
Q

What does increased peritubular capillary colloid osmotic pressure and decreased peritubular capillary hydrostatic pressure

A

Increased proximal Na reabsorption —>decreased excretion and H2O

63
Q

What does decreased casa recta flow lead to

A

Decreased washout of urea from medullary interstitial->increased urea, decreased Na in medullary interstitial->increased gradient for passive NaCl reabsorption by the thin ascending limb of henna->increased loop of henna Na reabsorption->decreased Na excretion and H2O excretion

64
Q

Action of aldosterone

A

Increases the synthesis of Na K ATPase in the basolateral membrane of the distal tubal

Overall result is an increase in Na reabsorption and an increase in K excretion

65
Q

Steps of aldosterone

A
  1. combines with a cytoplasmic receptor
  2. hormone receptor complex initiates transcription in the nucleus
  3. Translation and protein synthesis makes new protein channels and pumps
  4. Aldosterone induced proteins modulate existing channels and pumps
  5. Results is increased Na reabsorption and K secretion
66
Q

Actions of aldosterone

A

Increases the synthesis and activity NaK ATPase in the basolateral membrane of the distal tubule

Increases synthesis and activity of epithelial Na channels in apical membrane

Overall Na reabsorption and K excretion

67
Q

Aldosterone also stimulates tubular secretion of H

A

The apical membrane of a intercalated cells contain two transporters that secrete H into the tubular fluid:
HATPase
HK ATPase

Increase Na reabsorption
Increase K secretion
Increase H secretion

68
Q

Increased activity of __ is the first of four parallel pathways that correct a low effective circulating volume

A

RAAS

69
Q

Filtered load of Na=

A

(GFR)(plasmaNa)
=180L/day(14-mEq/L)
=25200 mEq/day

Want a consent amount of Na to be delivered to the distal tubules

Distal tubule fine tunes concentration to match dietary intake

70
Q

Na reabsorption in late DT and CD

A

Principal cells-Na and H20 reabsorption and K secretion

Responsible for fine adjustments in tubular fluid Na concentration

71
Q

Early proximal tubule-Na reabsorption

A

Na uptake across the apical membrane is coupled with movement of another molecule
-reabsorbed primarily with HCO3(not Cl), glucose, aa, Pa and lactate

Or

Reabsorbed in exchange for H or organic solutes

72
Q

Peritubular capillary symporters

A

Na glucose
Na aa
Na Pi
Na HCO3

Na into peritubular capillary

73
Q

Peritubular capillary antiporters

A

Na H
Na organic solutes
Na into peritubular capillary

74
Q

Reabsorption of Na in proximal tubule is driven by

A

NaK ATPase

75
Q

Early proximal tubules Na reabsorption

A

NaK ATPase pumps Na into the ISF outside basolateral membrane and is absorbed into the peritubular capillary

76
Q

Late proximal tubules Na reabsorption

A

Na uptake across the apical membrane is coupled with Cl
-reabsorbed primarily with Cl (transcellular)
-required operation of parallel transports happening simultaneously
-NaH antiporter
-Cl-base antiporter
Bases=formate oxalate and bicarbonate

Driven by NaK ATPase

77
Q

Late proximal tubules Na reabsorption

A

NaKAPTase pumps Na into the ISF outside basolateral membrane and is absorbed into the peritubular capillary. Cl crosses basolateral membrane via Cl channels

Reabsorption still driven by NaK ATPase

78
Q

Loop of Henley thin descending segment

A

Water permeable

NaCl remains in tubules-concentrates during descent

79
Q

Loop of Henley ascending limb

A

Thin and thick segment

Water impermeable

NaCl is reabsorbed in tubule

Dilutes during ascent

80
Q

Thick ascending limb

A

NaKATPase maintains low intracellular

Favors movement of Na from lumen into cell via NaK2Cl co transporter and NaH countertransporter

Luminal electrochemical gradient favors movement of other positively charged ions out of the tubule

Passive leakage of K and Cl

81
Q

Distal tubules early segment

A

Continuation of TAL

Juxtaglomerular apparatus

Reabsorbs Na Cl and Ca

Water impermeable

82
Q

Distal tubule late segment

A

Principal cells(Na reabsorption, K secretion…water reabsorption)

Intercalated cells (acid base balance)

Continues into collecting duct

83
Q

Early segment DT

A

NaKATPase maintains low intracelllular, favoring movement of Na into cell via NaCl cotransporter

Cl leaks out

Impermeable to water

84
Q

Late segment DT principle cells

A

NaKATPase maintains low intracellularNa, moving K into the cell

Na K and Cl diffuse down their concentration gradients

85
Q

Aldosterone antagonsits DT

A

Spironolactone
Eplerenone

(Eplerenone more specific than spironolactone)

Stop renal interstitial

86
Q

Na channel blockers DT

A

Amiloride
Triamterene

Stop luminal Na in

87
Q

PT water

A

67% filtered that’s reabsorbed

Passive osmosis

No hormones that regulate water permeability

88
Q

LOH water

A

15% filtered that’s reabsorbed

Passive osmosis (descending thin)

No hormones

89
Q

Early distal tubules water

A

0% filtered that’s reabsorbed

90
Q

Late distal tubule and collecting duct water

A

8-17% filtered that’s reabsorbed

Passive osmosis

ADH, ANP, BNP

91
Q

Water transport is __-

A

Passive

92
Q

Proximal tubules Na

A

67% filtered that’s reabsorbed

Primary and active transport

93
Q

LOH Na

A

35% filtered that’s reabsorbed

Secondary active transport

94
Q

DT Na

A

5% filtered that’s reabsorbed

Primary and secondary active transport

95
Q

Collecting duct Na

A

3% filtered that’s reabsorbed

Primary active transport

ADH, ANP, BNP

96
Q

Water and chloride __ sodium

A

Follow

97
Q

What increases ADH

A

Increase plasma osmolality

Decrease bp

Decrease blood volume

Nicotine

98
Q

What decreases ADH

A

Decrease plasma osmolality

Increase bp
Increase blood volume

Ethanol

99
Q

What increases thirst

A

Increased plasma osmolality

Decrease bp

Decrease bv

Increase angiotensin II

Dryness of mouth

100
Q

What decreases thirst

A

Decreased plasma osmolality

Increase bp

Increase bv

Decrease angiotensin II

Gastric distension

101
Q

Integrated response to volume expansion

A

GFR increases

Reabsorption of Na decreases int he proximal tubule and loop of henle

Na reabsorption decreases in the distal tubule and collecting duct

Water excretion follows

Hours->days

102
Q

What stimulates renin release in integrated response to ECV

A

Decreased bp (JGA)

Decreased NaCl delivery to the macula densa (NaCl sensor)

Decreased renal perfusion pressure (renal baroreceptors)

103
Q

Actions of angiotensin II in integrated response to decreased ECV

A

Increase aldosterone

Vasoconstriction efferent arteriole

Enhances NaH exchange (promotes Na reabsorption

Stimulates thirst and ADH release

104
Q

Sympathetic in integrated response to decreased ECV

A

Increase renal vascular resistance

Increased Na reabsorption

Enhances renin release (via JG cells)

105
Q

Major factor controlling ADH release in plasma osmolality

A

1% decrease in plasma osmolarity

5-10% decrease in ECV

106
Q

ANP is __ in integrated response to decreased ECV

A

Inhibited

107
Q

Integrated response to decreased ECV

A

GFR decreases
Na reabsorption by the proximal tubule and loop of henle is increased
Na reabsorption by the distal tubule and collecting duct is enhanced
Water reabsorption