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OSSF 2 > Exam 1- kidneys > Flashcards

Exam 1- kidneys Flashcards

1
Q

what cells produce renin?

A

juxtaglomerular cells

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2
Q

what does the macula densa do?

A

regulates bloodflow into the kidney

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3
Q

what are the homeostatic functions of the kidney?

A

blood/water volume
osmolarity
electrolytes
acid/base

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4
Q

what does the kidney produce?

A

renin
glucose
calcitriol
erythropoeitin

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5
Q

what is the main ion in regulating water volume?

A

sodium

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6
Q

what metabolic wastes are removed by the kidneys?

A

urea
creatinine
uric acid
allantoin
bilirubin

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7
Q

what does renin do?

A

forms angiotensin II, which works to increase blood volume

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8
Q

what cells produce erythropoeitin?

A

interstitial fibroblasts close to peritubular capillaries and proximal tubule

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9
Q

what is the preferred gluconeogenic substrate of the kidney?

A

glutamine

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10
Q

what cells perform gluconeogenesis?

A

proximal tubule epithelial cells

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11
Q

how much of the cardiac output do the kidneys receive? why?

A

20%
they need to filter all of the blood: control composition and volume of body fluids rapidly

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12
Q

what is the functional unit of the kidney?

A

nephron

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13
Q

what capillaries are in the kidneys?

A

fenestrated

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14
Q

what are the three steps of urine formation?

A

filtration
selective reabsorption
selective secretion

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15
Q

what is the fluid in the tubule called (descending/ascending)?

A

filtrate

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16
Q

how much of the plasma moves into the filtrate?

A

20%

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17
Q

what are the two capillaries in the kidney portal system?

A

glomerular
peritubular

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18
Q

what does the glomerular capillary do?

A

filters plasma

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19
Q

what does the peritubular capillary do?

A

reabsorbs a lot of filtrate and secretes some things

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20
Q

what substances’ clearance rates can be used to measure GFR?

A

inulin
iohexal
creatinine

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21
Q

what fluid is in the Bowman’s space?

A

ultrafiltrate

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22
Q

what are the three layers of the glomerular filtration barrier?

A

fenestrated endothelium with glycoprotein coat
basement membrane with heparin sulfate
podocyte foot processes with nephrin (diaphragm) and glycoprotein coat

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23
Q

what two characteristics do mesangial cells exhibit?

A

contractile and phagocytic

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24
Q

what is GFR?

A

the volume of fluid filtered per minute from the glomerular capillaries into Bowman’s space

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25
Q

what does the filtration coefficient in Starling’s equation for GFR depend on?

A

permeability and surface area of filtration barrier

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26
Q

what is the main way to change blood flow in the kidneys?

A

changing arteriolar resistance or diameter

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27
Q

why does the hydrostatic pressure in the glomerular capillaries stay almost constant throughout the length of the capillaries?

A

entering efferent arterioles (high resistance compared to venules)

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28
Q

what is part of autoregulation for GFR?

A

stretch receptors in afferent arteriole smooth muscle
paracrine (tubuloglomerular feedback)

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29
Q

what regulates GFR that is not autoregulation?

A

SNS
Renin-Angiotensin-Aldosterone System
Atrial natriuretic peptide/beta natriuretic peptide

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30
Q

what is pressure diuresis?

A

high blood pressure leads to increased urine output and Na excretion

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31
Q

what is the juxtaglomerular apparatus made up of?

A

macula densa (senses flow filtrate and NaCl in distal tube)
juxtaglomerular cells (afferent arteriole- makes renin)
extraglomerular mesangial cells

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32
Q

what are the paracrine factors that regulate GFR?

A

Vasoconstrictors: Adenosine, ATP, Endothelin
Vasodilators: Prostaglandins, Nitric oxide

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33
Q

what does angiotensin II do to regulate GFR and RBF?

A

constricts efferent (preferentially) and afferent arterioles
decreases hydrostatic pressure in peritubular capillaries

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34
Q

what do Atrial Natriuretic Peptide and Beta Natriuretic Peptide do?

A

dilate afferent arterioles (more) and constrict efferent arterioles
increase renal blood flow and GFR (opposite of RAAS)

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35
Q

how does the sympathetic nervous system affect renal blood flow?

A

vasoconstriction
alpha-1 receptors on afferent arterioles predominantly

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36
Q

what is renal clearance?

A

volume of plasma cleared of a substance by kidneys per unit time
ml/min

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37
Q

what is inulin?

A

a fructose polymer that can be used to calculate GFR because it is freely filtered by the kidneys
gold standard GFR

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38
Q

what is the main substance used by clinics to calculate GFR?

A

creatinine

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39
Q

does drinking more water have any effect on GFR?

A

no

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40
Q

true/false: creatinine in blood changes according to muscle mass

A

true

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41
Q

what is the GFR measuring substance that does not require urine collection?

A

iohexal

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42
Q

what does azotemia usually indicate?

A

decreased GFR

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43
Q

what are the caveats to using plasma creatinine to estimate GFR?

A
  1. plasma creatinine is an insensitive marker to GFR (20% of normal) (sequential measurement more helpful)
  2. assays not standardized
  3. muscle mass affects creatinine
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44
Q

what is Symmetric Dimethylarginine (SDMA)?

A

new test for assessing GFR in cats and dogs

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45
Q

what is Filtered Load?

A

amount of substance filtered per unit time

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46
Q

is glucose found in a healthy animal’s urine?

A

no

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47
Q

what happens to sodium after it is filtered into the ultrafiltrate?

A

most of it is reabsorbed

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48
Q

what is special about potassium excretion in the kidneys?

A

after the initial glomerular filtration, more is added in the distal tubule

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49
Q

what is the Clearance Ratio?

A

clearance of any molecule compared to clearance of inulin (GFR)

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50
Q

what should the Clearance Ratio be for Na?

A

<1%

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51
Q

what does Angiotensin II during a mild decrease in MAP?

A

preferentially constricts efferent arterioles to decrease RBF and maintain GFR

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52
Q

what does Angiotensin II do during a hemorrhage?

A

constricts both efferent and afferent arterioles to have a small decrease in GFR and RBF
leads to decrease hydrostatic pressure peritubular capillaries: reabsorption water/ions, maintain ECF

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53
Q

what type of cells make up the outer wall of the Bowman’s Capsule?

A

simple squamous epithelium

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54
Q

what do mesangial cells produce?

A

mesangial matrix
several types cytokines

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55
Q

what detects flow rate in the macula densa?

A

primary cilia (monocilia)

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56
Q

which arteries enter the cortex in the kidney?

A

interlobular arteries

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57
Q

what does the vasa recta do?

A

reclaims water as urine is concentrated

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58
Q

what cells does the proximal convoluted tubule have?

A

tall cuboidal cells with basal nucleus

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59
Q

what does the Loop of Henle do?

A

moves salt and urea into interstitial space to create hypertonic interstitial space

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60
Q

where is transitional epithelium (urothelium) located?

A

renal calyx, renal pelvis
ureter
bladder
proximal urethra

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61
Q

what species have multilobar kidneys?

A

humans
cows
pigs
marine mammals

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62
Q

what is a renal infarct?

A

bloodflow is blocked to a section of kidney, leading a triangle to die

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63
Q

what is in the renal corpuscle?

A

Bowman’s capsule
glomerular tuft/glomerulus
mesangial cells
juxtaglomerular apparatus

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64
Q

what does macula densa do when flow rate or Na decrease?

A

secretes vasodilator

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65
Q

what is in the cortex histologically?

A

renal corpuscles (glomeruli)
convoluted and straight tubules
collecting tubules and ducts

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66
Q

what is in the medulla histologically?

A

straight tubules
collecting tubules and ducts
vasa recta

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67
Q

what areas are most vulnerable to ischemia and nephrotoxins?

A

areas with more mitochondria and cellular activity

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68
Q

what is the major site of reabsorption?

A

proximal convoluted tubule

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69
Q

what are the three sections of the loop of Henle?

A

descending limb (proximal straight tubule)
thin segment
thick ascending limb (distal straight tubule)

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70
Q

what do the loop of Henle and vasa recta establish?

A

osmotic gradient in medulla

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71
Q

what conserves Na via the Na/K ATPase and balances acid and base?

A

distal convoluted tubule

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72
Q

how can the collecting system be distinguished histologically?

A

clearly defined cell margins
clean lumenal space
2 types cuboidal epithelium

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73
Q

does the distal convoluted tubule have taller or lower cuboidal cells than the proximal convoluted tubule?

A

lower (also less distinct brush border or not visible)

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74
Q

what do the principal cells in the collecting system do?

A

insert aquaporins into membrane
respond to antidiuretic hormone

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75
Q

what do the intercalated cells in the collecting system do?

A

acid/base function

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76
Q

what is found in the inner medulla?

A

thin limbs loop of Henle
collecting ducts
vasa recta

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77
Q

what are the two types of nephrons?

A

cortical nephrons
juxtamedullary nephrons

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78
Q

where is most of the connective tissue found in the kidney located?

A

medulla

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79
Q

what does transitional epithelium (urothelium) produce?

A

antimicrobial molecules

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80
Q

what is in the tunica muscularis in ureters?

A

thin inner longitudinal
outer circular
extra longitudinal bundle at distal end

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81
Q

what is the outer layer of the bladder vs the ureter?

A

tunica serosa
tunica adventitia

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82
Q

what is the progression of epithelium in the female urethra?

A

urothelium proximally
stratified cuboidal
stratified squamous distally

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83
Q

what are the two regions of the canine male urethra?

A

prostatic
postprostatic

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84
Q

what are the three regions of the feline male urethra?

A

preprostatic
prostatic
postprostatic

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85
Q

where is the striated urethralis muscle located?

A

female: caudal 1/3 urethra
male: postprostatic region

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86
Q

what do the female cranial urethra and feline male urethra preprostatic have in common?

A

urothelium and smooth muscle is here (no smooth muscle cranially in male canine urethra)

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87
Q

what is the filtration fraction?

A

the amount of plasma presented to the kidneys that gets filtered through glomeruli (20-25%)

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88
Q

what are the morphological changes in the kidneys associated with aging?

A

loss nephron mass
glomerular sclerosis
loss of filtration surface area

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89
Q

what is proximal tubular P-aminohippurate (PAH) secretion mediated by?

A

organic anion transporters ((g)OAT)

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90
Q

why is creatinine not the gold standard for measuring GFR?

A

in primates there is secretion of it too
slightly off in dogs and cats

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91
Q

does a healthy kidney secrete sodium?

A

never ever

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92
Q

what is transcellular reabsorption?

A

two-step process which uses transporters or channels

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93
Q

what facilitates secondary active transport?

A

Na/K ATPase (pumping Na into blood)

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94
Q

what is the Na-coupled proximal tubular “symport” process used for?

A

amino acids
glucose
lactate, citrate, phosphate…

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95
Q

true/false: glucose is freely filtered and therefore glucose filtration is exactly proportional to the plasma concentration

A

true

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96
Q

what is renal threshold?

A

the minimal plasma glucose level at which excretion begins (no longer reabsorbing it all)

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97
Q

what receptors are used for capturing small proteins and peptides in the urine?

A

megalin and cubilin

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98
Q

how much insulin is excreted?

A

very little (almost 0)

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99
Q

what takes up secreted cations?

A

organic cation transporters in basal membranes in the tubular epithelium

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100
Q

is sodium reabsorbed in one or multiple parts of the nephron?

A

multiple

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101
Q

how is renal plasma flow estimated?

A

with the effective renal plasma flow (ERPF): amount of plasma cleared of p-aminohippuric acid (PAH) per unit time

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102
Q

what is true RPF?

A

ERPF/PAH renal extraction efficiency= 200/0.9 =~220 ml/min

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103
Q

what does the difference between the filtered load and the clearance of a substance indicate?

A

the net reabsorption and/or secretion

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104
Q

if the filtered load is greater than the excretion rate, what does this say about how the kidney is handling that drug?

A

it is reabsorbing the drug from the filtrate

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105
Q

what is the order of membranes/walls gone through for transcellular reabsorption?

A
  1. apical membrane
  2. epithelial cell cytosol
  3. basolateral membrane
  4. interstitial fluid
  5. capillary wall
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106
Q

what are the two types of reabsorption?

A

transcellular and paracellular reabsorption

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107
Q

what are the renal glucose transporters?

A

GLUT and SGLT (sodium glucose linked transporter)

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108
Q

where is most of the glucose reabsorbed?

A

S1 segment of the proximal tubule (SGLT2 and GLUT2)

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109
Q

what are two possibilities for glucose in urine?

A

hyperglycemia
defect in glucose reabsorption

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110
Q

how are amino acids reabsorbed?

A

secondary active transport
transcellular absorption in proximal convoluted tubules

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111
Q

how are organic cations secreted?

A

organic cation transporters (OCT), driven by negative membrane potential

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112
Q

what does a low pH urine do to weak acids?

A

protonates them and enhances their reabsorption

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113
Q

when is clearance of a weak acid highest (alkaline or acid pH)?

A

alkaline urine pH

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114
Q

how do most terrestrial animals excrete amino nitrogen?

A

allantoin
urea

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115
Q

what is articular gout?

A

uric acid crystal accumulation in joints and along tendons due to renal failure

116
Q

where is urea transported in the nephron?

A

in most segments

117
Q

how is urea transported?

A

simple or facilitated diffusion

118
Q

what does urea do in the thin descending limb?

A

it is secreted up to 110% of the filtered load

119
Q

where is impermeable to urea?

A

thin ascending limb
distal tubule
cortical an outer medullary collecting ducts

120
Q

what is the last place urea is reabsorbed?

A

inner medullary collecting ducts

121
Q

what does urea recycling contribute to?

A

corticopapillary osmotic gradient which is critical in determining the final osmolarity of urine

122
Q

true/false: the urine pH can affect both solubility and reabsorption of weak acids and bases

A

true

123
Q

why is sodium reabsorption in the kidney important?

A

driving force for reabsorption of organic substances and other ions
coupled with secretion of potassium and hydrogen ions

124
Q

what is the major cation in ECF compartment?

A

sodium

125
Q

what forces are in play in peritubular capillaries?

A

low hydrostatic pressure
high protein oncotic pressure

126
Q

in what tubule is water and sodium reabsorption linked?

A

proximal tubule

127
Q

where is the majority of sodium reabsorption?

A

proximal tubules and loop of Henle

128
Q

what is transepithelial potential difference important in driving?

A

calcium and magnesium reabsorption
potassium secretion

129
Q

how are solutes reabsorbed?

A

transcellular and paracellular

130
Q

what is the major anion co-transported with sodium in the early proximal tubule?

A

bicarbonate (HCO3-)

131
Q

why is HCO3- important?

A

critical buffer in maintaining physiological pH

132
Q

what is the major anion co-transported with sodium in the late proximal tubule (S3)?

A

chloride (Cl-)

133
Q

what happens to the [tubular fluid]/[systemic plasma] of Na+ as the filtrate goes through the proximal tubule?

A

stays the same at 1 because of isosmotic reabsorption

134
Q

what happens to the [tubular fluid]/[systemic plasma] of glucose and amino acids as the filtrate goes through the proximal tubule?

A

decreases

135
Q

is the ascending limb of the loop of Henle permeable to water?

A

no

136
Q

what is the diluting segment of the nephron?

A

thick ascending limb and the distal convoluted tubule

137
Q

what is transported in the thick ascending limb by the cotransporter?

A

Na+, K+, 2Cl-

138
Q

where is the Na+-Cl- cotransporter?

A

early distal tubule

139
Q

what is the major site of REGULATED tubular reabsorption?

A

late distal tubule and collection ducts

140
Q

how does aldosterone affect epithelial Na+ channels (ENaC) in principal cells?

A

increases the channels

141
Q

what is ECF potassium critical to?

A

excitability of nerves and muscle tissue

142
Q

what is the main intracellular cation?

A

potassium

143
Q

what does insulin do to Na/K ATPase?

A

increases its activity

144
Q

what is the progression of K+ reabsorption and secretion after the glomerulus?

A

67% reabsorbed in proximal tubule
20% reabsorbed in thick ascending limb
reabsorbed in the distal tubule with low K+ diet (intercalated cells)
variable secretion in collecting ducts and distal convoluted tubule (principal cells)

145
Q

what happens when there is a high K+ diet?

A

insulin pushes K+ into the cells via Na/K ATPase
secreted by principal cells through apical K+ channels

146
Q

is aldosterone triggered by increased or decreases K+ intake?

A

increased

147
Q

what organs are involved in calcium homeostasis?

A

intestine
bone
kidney

148
Q

what stimulates calcium reabsorption at the distal tubule?

A

parathyroid hormone (PTH)

149
Q

where is calcitonin produced?

A

thyroid parafollicular cells (clear or C)

150
Q

what does calcitonin do?

A

decreases Ca++ in ECF

151
Q

what do organic cation transporters do?

A

take up secreted cations in basal membranes of tubular epithelium

152
Q

how does parathyroid hormone regulate phosphate excretion?

A

negatively regulates Na/Phosphate cotransporter which reabsorbs phosphate

153
Q

what is the gold standard for measuring urine solute concentration?

A

osmolality

154
Q

what is hyposmotic urine?

A

<300mOsm/L
more dilute than plasma

155
Q

what affects specific gravity?

A

number of solute particles per liter of solution
color and turbidity
temperature

156
Q

how does the refractometer measure specific gravity?

A

refractive index correlated against specific gravity

157
Q

what is the term for hyperosmotic urine?

A

hypersthenuric

158
Q

what part of the nephron is NOT permeable to water?

A

ascending thin limb through the distal convoluted tubule (proximal part)

159
Q

what part of the nephron is under regulation for water reabsorption? what regulates it?

A

late distal convoluted tubule and collecting duct
antidiuretic hormone

160
Q

what three things does antidiuretic hormone affect?

A

water permeability (principal cells) (aquaporins)
urea permeability (UT1)
Na/K/2Cl transporter (countercurrent multiplication)

161
Q

what do the principal cells do?

A

reabsorb NaCl
secrete K+
variable water reabsorption

162
Q

how does the loop of Henle act as a countercurrent multiplier?

A

deposits NaCl in the deeper interstitial fluid medulla
descending limb almost impermeable to ions/solutes
thick ascending limb almost impermeable to water

163
Q

how is NaCl deposited in the interstitial fluid in the deeper medulla (passive vs active transport)?

A

passive through Na channels initially
thick limb: active transport via apical Na/K/2Cl transporter and Na/K ATPase

164
Q

how is urea reabsorbed in the proximal tubule?

A

paracellularly without transporters

165
Q

what drives secretion of urea in the thin descending limb?

A

high concentration urea in the interstitial fluid

166
Q

without antidiuretic hormone, will more or less urea be excreted?

A

more urea

167
Q

what does production of hypersthenuric urine require?

A

production of ADH
receptors for ADH
hypertonic interstitium: NaCl and urea

168
Q

how and where is filtrate diluted to produce dilute urine?

A

thick ascending limb reabsorbs NaCl: hypotonic filtrate
early distal tubule reabsorbs NaCl by Na/Cl cotransporter
late distal tubule and collecting duct reabsorb more Na/Cl

169
Q

what happens when less antidiuretic hormone (ADH) is secreted?

A

no aquaporins inserted into collecting ducts: impermeable

170
Q

what dictates the relative proportion of water in the extracellular vs intracellular fluid?

A

gain or loss of sodium

171
Q

what does infusion of isotonic saline do to the extracellular and intracellular fluids?

A

increases the amount of extracellular fluid and keeps the intracellular fluid the same

172
Q

why does water follow sodium?

A

to keep the osmolarity constant, sodium and water are paired in their excretion for the most part

173
Q

what does angiotensin II do with Na+ reabsorption in the proximal tubule?

A

stimulates Na/K ATPase and Na+-H+ exchange to reabsorb

174
Q

what does angiotensin II stimulate in the distal tubule and collecting ducts?

A

Na channels and Na/Cl symporters

175
Q

how does aldosterone promote potassium secretion?

A

inserts channels into apical lumen
Na/K ATPase (Na into cell, K into filtrate)

176
Q

how does natriuretic peptide affect epithelial sodium channels (ENaC)?

A

decreases it to decrease Na reabsorption in the late distal tubule and collecting ducts

177
Q

what does an increase in ECF volume mean for peritubular capillaries and Starling forces?

A

inhibit proximal tubule sodium reabsorption

178
Q

what species secretes mucus in its proximal ureter and renal pelvis?

A

horse

179
Q

what valve keeps the urine from backflowing?

A

vesicoureteral valves

180
Q

what is needed to allow the bladder to fill without emptying?

A

sympathetic innervation: contraction internal urinary sphincter and relaxation of detrusor muscle

181
Q

what opens the internal urinary sphincter?

A

high pressure from bladder (detrusor muscle contraction) and PNS input

182
Q

what animals can get most of their water from metabolism?

A

desert rodents

183
Q

what do bony fishes rely on more for eliminating excess or waste solutes?

A

tubular secretion

184
Q

how can ammonia leave freshwater fish?

A

through their gills

185
Q

what is the nitrogenous waste product of reptiles and birds?

A

uric acid

186
Q

do birds have a urinary bladder?

A

no- urine enters cloaca

187
Q

what percent of nephrons are functional at a given time?

A

10%

188
Q

where do the juxtamedullary nephron renal corpuscles sit in reference to the cortex and medulla?

A

at the junction between

189
Q

why is H+ transported into the filtrate? (sodium into cell, hydrogen into filtrate)

A

to combine with bicarbonate, to move CO2 and H2O across the membrane into lumen-lining cell
it then turns into H+ and bicarbonate again, bicarbonate moves into blood as buffer

190
Q

what is the sequence of blood vessels between the renal artery and the renal vein?

A

renal artery
afferent arteriole
glomerular capillary
efferent arteriole
peritubular capillaries (in cortex)
vasa recta (in medulla)
renal vein

191
Q

what is osmolality vs osmolarity?

A

osmolality: dissolved particles per kilogram
osmolarity: dissolved particles per liter

192
Q

what is the range for normal blood pH?

A

~7.38-7.44

193
Q

why is pH regulation important?

A

pH is tightly regulated to keep it appropriate because enzyme activity is dependent upon appropriate pH

194
Q

what is alkalemia?

A

increased blood pH

195
Q

what is acidosis?

A

physiologic condition that acts to increase H+ concentration

196
Q

how can physiologic pH be maintained? (both healthy and not)

A

buffering
compensation
mixed acid-base abnormalities

197
Q

do stronger acids have higher or lower pKa values?

A

lower

198
Q

are weak acids or strong acids completely dissociated at physiologic pH?

A

strong acids
weak acids incompletely dissociated

199
Q

how is the Henderson-Hasselbalch equation used?

A

to estimate pH of buffer solution

200
Q

what is the primary extracellular buffer in blood/plasma?

A

bicarbonate

201
Q

what does carbon dioxide form when dissolved in aqueous solutions?

A

carbonic acid

202
Q

how are non-volatile acids dealt with?

A

metabolized or excreted

203
Q

what are the sources of CO2 in the body?

A

carbohydrate oxidation
beta oxidation of fatty acids

204
Q

does anaerobic glycolysis produce a volatile or non-volatile acid?

A

non-volatile (lactic acid)

205
Q

what protein in blood does a lot of bufferimg?

A

hemoglobin

206
Q

where is the phosphate buffer system most important?

A

intracellularly and in urine

207
Q

what is the isohydric principle?

A

all the buffer systems acting on blood are in equilibrium vie their shared component, [H+]
therefore, we can evaluate acid-base balance by evaluating just one of the buffer systems

208
Q

what enzyme catalyzes the conversion of CO2 and H2O to carbonic acid?

A

carbonic anhydrase

209
Q

how can [H2CO3] be estimated?

A

with paCO2

210
Q

what does bicarbonate concentration reflect?

A

metabolic regulation

211
Q

what does PCO2 reflect?

A

respiratory regulation

212
Q

where is most of the renal regulation of metabolic acid-base balance?

A

distal tubule and collecting duct

213
Q

how is bicarbonate transported back into blood in the proximal tubule?

A

Na+/HCO3- symporter

214
Q

what do A-intercalated cells do?

A

directly secrete H+ at the apical membrane

215
Q

what do B-intercalated cells do to the blood?

A

acidify the blood by secreting HCO3- and reabsorbing H+

216
Q

how does the liver alkalinize the blood?

A

gluconeogenesis using lactate

217
Q

why does the renal ammonium excretion happen?

A

non-acidifying because preserves bicarbonate
glutamine converted to glutamate and ammonium, which is excreted in urine

218
Q

what is metabolic acidosis?

A

decreased bicarbonate

219
Q

what is respiratory alkalosis?

A

decreased CO2

220
Q

what regulates ventilation?

A

central chemoreceptors in the medulla
peripheral chemoreceptors in the carotid and aortic bodies

221
Q

what molecule is important in brain ECF pH changes?

A

CO2

222
Q

what is titration for metabolic acidosis?

A

accumulation of an endogenous or exogenous organic acid (bicarb lost as it buffers acid, anion gap increased)

223
Q

why is anion gap useful?

A

it helps to differentiate between titration and secretion acidosis

224
Q

what is the traditional analysis for total carbon dioxide?

A

a strong acid is added to serum and the CO2 that is released is measured

225
Q

if PCO2 is increased, what does it indicate?

A

respiratory acidosis

226
Q

if total carbon dioxide is increased, what does is indicate?

A

metabolic alkalosis

227
Q

is respiratory or metabolic compensation faster?

A

respiratory

228
Q

what is compensation trying to do regarding the ratio of bicarbonate and PCO2?

A

trying to maintain the ratio at normal

229
Q

what limits compensation for metabolic alkalosis?

A

the need for adequate oxygenation

230
Q

what does addition of an organic acid do to the anion gap?

A

increases it

231
Q

what can lactic acidosis result from?

A

increased anaerobic glycolysis

232
Q

what are the types of lactic acidosis?

A

type A and type B

233
Q

what does type A lactic acidosis result from?

A

oxygen deficit

234
Q

what does type B lactic acidosis result from?

A

decreased metabolism of lactate and/or from increased lactate production

235
Q

what do increased levels of ketones cause?

A

titration-type acidosis

236
Q

what are three conditions that cause ketosis/ketoacidosis?

A

diabetes mellitus
starvation
bovine ketosis

237
Q

can renal failure cause acidosis?

A

yes

238
Q

what are three different options for an acidic blood pH?

A

secretion metabolic acidosis
titration metabolic acidosis
respiratory acidosis

239
Q

does a larger anion gap indicate titration acidosis or secretion acidosis?

A

titration acidosis

240
Q

what does ethylene glycol poisoning cause?

A

titration acidosis directly, and induce renal failure

241
Q

what are the two causes of secretion metabolic acidosis?

A

urinary bicarbonate loss or GI bicarbonate loss

242
Q

what leads to urinary bicarbonate loss (decreased reabsorption)?

A

renal tubular disease/renal tubular acidosis
compensation for chronic respiratory alkalosis

243
Q

if a patient is acidotic, should their urine be aciduria or alkaluria?

A

aciduria

244
Q

what is Fanconi’s syndrome?

A

a disease most common in basenjis where the renal tubules are not reabsorbing glucose, bicarbonate, sodium, potassium, urates, cystine/amino acids as they should

245
Q

true/false: renal tubular acidosis is caused by a lower pH in the renal tubules and urine

A

false. it is caused by renal tubular dysfunction

246
Q

where can renal tubular acidosis arise?

A

proximal tubule and/or distal tubule

247
Q

true/false: proximal tubular acidosis is characterized by a defect in HCO3- reabsorption in the proximal tubules

A

true

248
Q

what does distal tubular acidosis mean in terms of what is being secreted/absorbed incorrectly?

A

defect in H+ secretion

249
Q

what are the causes of metabolic alkalosis?

A

increased base/buffer levels
loss of H+ (and Cl)
dehydration with Cl- loss and/or K+ depletion

250
Q

why does vomiting lead to an increase in bicarbonate in the blood?

A

carbonic anhydrase produces both H+ and bicarbonate from CO2 and water, the H+ is being lost

251
Q

what causes “alkaline tide”?

A

increased gastric acid production due to vomiting or eating (postprandial)

252
Q

are pancreatic secretions into the duodenum high or low pH?

A

high

253
Q

should patients with only metabolic alkalosis have a normal anion gap?

A

yes. bicarbonate gain balanced by chloride loss

254
Q

does dehydration lead to metabolic alkalosis or acidosis on its own?

A

metabolic alkalosis (concentration bicarbonate increased)

255
Q

what does hypoalbuminemia lead to? (alkalosis or acidosis)

A

alkalosis, unmeasured ion too

256
Q

how can mixed metabolic conditions be recognized (HCO3 and TCO2 levels normal)?

A

high anion gap or high lactate level

257
Q

what can cause a decreased anion gap?

A

artifact
decreased unmeasured anions
increased unmeasured cations

258
Q

what does acidemia do to ionized calcium?

A

increases it because H+ competes with calcium for albumin binding sites

259
Q

what does K+ do in alkalosis?

A

serum K+ may decrease (moves into cells as H+ moves out)

260
Q

what does Stewart’s Theorem look at?

A

quantitative acid-base balance

261
Q

what does an increased strong ion difference indicate?

A

metabolic alkalosis

262
Q

what does a decreased strong ion difference indicate?

A

titration or secretion metabolic acidosis

263
Q

how can titration vs secretion acidosis be distinguished?

A

look at the lactate and ketones
anion gap
strong anion gap

264
Q

should a decreased strong ion difference have a low or high PCO2?

A

decreased PCO2

265
Q

does dilution of blood cause a change in the strong ion difference?

A

yes, disproportionately affects sodium because its’ concentration is higher

266
Q

what happens to most small proteins and peptides filtered through the glomerular capillary filter?

A

reabsorbed in proximal tubule via endocytosis

267
Q

what pressure increases as you move down the glomerular capillary?

A

plasma oncotic pressure

268
Q

what is myogenic control of blood flow in the kidneys?

A

autoregulation of GFR and RBF: stretch arterial walls leads to a reflex muscle contraction to decrease blood flow

269
Q

what are the two main factors that alter glomerular filtration rate?

A

changes in renal blood flow
changes in glomerular capillary hydrostatic pressure

270
Q

what is reabsorbed in the proximal convoluted tubule?

A

Na+
glucose
amino acids
phosphate
lactate
citrate

271
Q

is urothelium permeable to water and salts?

A

no

272
Q

for which solutes is the proximal tubule the MAJOR site of reabsoprtion?

A

glucose
phosphate
chloride
potassium
sodium
water
amino acids

273
Q

what is the site of major reabsorption for magnesium?

A

thick ascending limb

274
Q

what does parathyroid hormone regulate?

A

stimulates Ca++ reabsorption (thick ascending limb)
inhibits phosphate reabsorption (proximal tubule) (Na/Phosphate symporter)

275
Q

what regulates epithelial Na+ channels?

A

aldosterone increases
atrial natriuretic peptide decreases

276
Q

what does aldosterone do?

A

stimulates K+ channels
stimulates Na/K ATPase
stimulates Na+ channels

277
Q

how do camels minimize their water loss?

A

raise their body temperature
dry feces and concentrated urine

278
Q

why is blood in cartilaginous fishes isotonic with sea water?

A

high urea levels

279
Q

what fish have a renal portal system?

A

bony fishes and freshwater fishes

280
Q

can reptiles absorb water through the wall of the rectum or cloaca?

A

yes

281
Q

does a reptile kidney have loops of Henle?

A

no

282
Q

which glucose transporter is in the apical membrane versus the basolateral membrane?

A

apical membrane: sodium glucose linked transporters
basolateral membrane: glucose transporters

283
Q

how is the sodium glucose transporter (SGLT-1 isoform) different in the late proximal tubule?

A

transports two sodiums per glucose instead of one

284
Q

where are amino acids reabsorbed?

A

proximal convoluted tubules

285
Q

where are anions and cations mainly secreted?

A

proximal tubules
transporters (OAT and OCT) in basal membranes
MDR1 and MDR2 in apical membranes for anions

286
Q

are there urea transporters in the proximal tubule?

A

no

287
Q

what are the postprostatic male layers of the urethra?

A

stratified squamous
stratum spongiosum
striated urethralis muscle

OSSF 2 (19 decks)

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