CIULLA_LIVER FUNCTION & PORPHYRIN FORMATION Flashcards

1
Q

Principal pigment in bile that is derived from hemoglobin breakdown

A

Bilirubin

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2
Q

From what system is bilirubin produced

A

reticuloendothelial system

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3
Q

Bilirubin is produced from the breakdown of ____.

A

hemoglobin from senescent red blood cells (RBCs)

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4
Q

Prior to transport to the liver, bilirubin forms a complex with _______.

A

albumin

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5
Q

Upon forming a complex with albumin, bilirubin is (conjugated/unconjugated) and (is/not) water-soluble.

A

unconjugated, not water soluble

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6
Q

Where is bilirubin conjugated

A

hepatocyte endothelial system

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7
Q

Product of conjugation of bilirubin and glucuronic acid

A

bilirubin diglucuronide (conjugated bilirubin)

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8
Q

Reaction of bilirubin and glucuronic acid is catalyzed by ________.

A

uridine diphosphate (UDP) glucuronyltransferase

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9
Q

T/F:

Conjugated bilirubin is water-soluble.

A

TRUE

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10
Q

Conjugated bilirubin is excreted into what form prior to storage in the gallbladder?

A

bile

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11
Q

Conjugated bilirubin is stored in the ______.

A

gallbladder

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12
Q

Pathways of urobilinogen

A

Intestinal urobilinogen: reabsorbed
Portion returns to the liver
Some enters the circulation for excretion in the urine

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13
Q

Once conjugated bilirubin is excreted into bile, and secreted into the duodenum in response to gallbladder stimulation, it is further reduced by anaerobic bacteria in the intestine to _______.

A

urobilinogen

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14
Q

Some bilirubin is oxidized by anaerobic bacteria for excretion in the stool in the form of ______.

A

urobilin

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15
Q

an orange-brown pigment that gives stool its characteristic color.

A

urobilin

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16
Q

a yellow discoloration that occurs when the bilirubin concentration in the blood rises and the bilirubin is deposited in the skin and sclera of the eyes.

A

jaundice

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17
Q

what concentration of bilirubin will jaundice be considered?

A

> 2-3 mg/dL

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18
Q

Elevated bilirubin deposits in brain tissue of infants, affecting the central nervous system and resulting in mental retardation.

A

kernicterus

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19
Q

Bile is secreted by _____.

A

liver

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20
Q

Bile is stored in the _______.

A

gallbladder

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21
Q

Composition of bile salts

A

cholic acid

chenodeoxycholic acid conjugated with glycine or taurine

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22
Q

the primary site in the

body for synthesis of waste products

A

liver

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23
Q

the primary site in the
body for d conversion of drugs to metabolites for
excretion in urine or stool

A

liver

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24
Q

type of jaundice which occurs when there is excessive erythrocyte destruction, as seen in hemolytic anemias, spherocytosis, toxic conditions, hemolytic disease of the newborn caused by Rh or ABO incompatibility

A

Pre-hepatic jaundice

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25
Q

type of jaundice where the rate of hemolysis exceeds the liver’s ability to take up the bilirubin for
conjugation.

A

pre-hepatic jaundice

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26
Q

prehepatic jaundice is characterized by an increased level of what type of bilirubin

A

unconjugated

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27
Q

type of jaundice which occurs when the liver cells malfunction and cannot take up, conjugate, or secrete bilirubin

A

hepatic jaundice

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28
Q

defect in the ability of hepatocytes to take up

bilirubin; due to transport problem of bilirubin from the sinusoidal membrane to the microsomal region

A

Gilbert syndrome

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29
Q

Gilbert syndrome is a transport problem of bilirubin to what sites?

A

from sinusoidal membrane to microsomal region

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30
Q

BILIRUBIN CONDITION (dec/inc)

Gilbert syndrome

A

mild increase in serum level of unconjugated bilirubin (1.5-3.0 mg/dL)

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31
Q

Partial or complete deficiency of UDP-glycuronyltransferase

A

Crigler-Najjar disease

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32
Q

BILIRUBIN CONDITION (dec/inc)

Crigler-Najjar disease

A

moderate to extremely elevated serum level of unconjugated bilirubin

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33
Q

defective liver cell excretion of bilirubin due
to impaired transport in the hepatocyte of conjugated bilirubin from
microsomal region to the bile canaliculi

A

Dubin-Johnson syndrome

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34
Q

Dubin-Johnson syndrome is an impaired transport in the hepatocyte of conjugated bilirubin to what sites?

A

from microsomal region to bile canaliculi

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35
Q

BILIRUBIN CONDITION (dec/inc)

Dubin-Johnson syndrome

A

increased serum conjugated bilirubin

mild increase in unconjugated bilirubin

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36
Q

Level of UDP-glycuronyltransferase is

low at birth;

A

Neonatal physiological jaundice

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37
Q

BILIRUBIN CONDITION (dec/inc)

neonatal physiological jaundice

A

increased serum unconjugated bilirubin

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38
Q

may be caused by hepatocyte injury such as

cirrhosis, bile duct injury such as Rotor syndrome, or neoplasms

A

Intrahepatic cholestasis

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39
Q

type of jaundice which occurs when an obstruction blocks the flow of bile into the intestines.

A

Posthepatic jaundice

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40
Q

BILIRUBIN CONDITION (dec/inc)

posthepatic jaundice

A

significantly increased serum conjugated bilirubin
increased serum unconjugated bilirubin
increased conjugated bilirubin in urine
decreased urine and fecal urobilinogen

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41
Q

In posthepatic jaundice, the stool appears (pale/dark) in color

A

pale

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42
Q

a condition wherein obstruction blocks the flow of bile into the intestines

A

extrahepatic cholestasis

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43
Q

extrahepatic cholestasis samples

A
gallstones obstructing common bile duct
neoplasms (carcinoma of ampulla of Vater, carcinoma of pancreas)
inflammatory conditions (acute cholangitis, acute pancreatitis)
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44
Q

result of chronic scarring of liver tissue turning it into nodules

A

cirrhosis

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45
Q

Causes of cirrhosis:

A

excessive alcohol ingestion for long periods of time
hemochromatosis
hepatitis complication

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46
Q

primary cancer of the liver is referred to as

A

hepatocellular carcinoma/hepatoma

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47
Q

Arise from other cancerous tissue where the primary site was of lung, pancreas, gastrointestinal tract, or ovary origin

A

metastatic liver tumors

48
Q
a liver disorder with an unknown cause. Symptoms include encephalopathy, neurologic abnormalities including seizures or coma, and abnormal liver
function tests due to hepatic destruction.
A

Reye syndrome

49
Q

Population where Reye syndrome mainly occurs

A

children

50
Q

Reye syndrome occurs mainly in children after what conditions?

A

After viral infection (varicella or influenza)

After aspirin therapy

51
Q

Drugs that may cause liver damage

A

phenothiazine
antibiotics
antineoplastic drugs
anti-inflammatory drugs (acetaminophen)

52
Q

markers for hepatocellular necrosis

A

ALT
AST
LD

53
Q

enzyme marker most specific for hepatocyte injury

A

ALT

54
Q

enzyme marker to assess liver function less specific than ALT; significant presence in other tissues

A

AST

55
Q

least specific enzyme marker to assess liver function with significant presence in other tissues

A

LD

56
Q

enzyme markers that reflect cholestasis

A
alkaline phosphatase (ALP)
Gamma-glutamyl transferase (GGT)
57
Q

A condition which impairs the flow of bile from the liver to the small intestine by either slowing or stopping the flow.

A

Cholestasis

58
Q

Other tests to assess liver disorders (aside from enzyme markers)

A

Total bilirubin, direct bilirubin, indirect bilirubin
Albumin
Ammonia
AFP

59
Q

test methodology for bilirubin (total bilirubin test)

A

Jendrassik-Grof total bilirubin test

60
Q

Sources of error for bilirubin determination

A

Hemolysis
Lipemia
Light exposure (sunlight and fluorescent)

61
Q

How is bilirubin concentration read for newborns?

A

Direct spectrophotometry

62
Q

In direct spectrophotometry (bilirubin), concentration is proportional to absorbance at ______ nm.

A

455 nm

63
Q

BILIRUBIN REFERENCE RANGE:

Infants Total bilirubin

A

2-6 mg/dL (0-1 day, full term)

64
Q

BILIRUBIN REFERENCE RANGE:

Adults Total Bilirubin

A

0.2-1.0 mg/dL

65
Q

BILIRUBIN REFERENCE RANGE:

Adults Indirect bilirubin

A

0.2-0.8 mg/dL

66
Q

BILIRUBIN REFERENCE RANGE:

Adults Direct Bilirubin

A

0.0-0.2 mg/dL

67
Q

collective term for stercobilinogen, mesobilinogen, and

urobilinogen.

A

urobilinogen

68
Q

end-color of product of urine urobilinogen assay

A

red color

69
Q

urine urobilinogen assay equation

A

urobilinogen + p-dimethyl aminobenzaldehyde = red colored complex

70
Q

sources of error for urobilinogen testing

A

oxidation occurs in standing urine

reacting of other compounds (porphobilinogen)

71
Q

In posthepatic obstruction, urobilinogen formation is (increased/decreased).

A

decreased

Due to impaired bilirubin excretion into the intestines

72
Q

color of stool in partial biliary obstruction

A

clay-colored

73
Q

color of stool in complete biliary obstruction

A

chalky white

74
Q

increased urine urobilinogen is associated to what conditions

A
hemolytic disease
hepatocellular diseases (e.g., hepatitis)
75
Q

Urine urobilinogen reference range

A
  1. 1-1.0 Ehrlich units/2 hr

0. 5-4.0 EU/d or (+1)

76
Q

Feces urobilinogen reference

A

75 - 400 EU/d (or +2)

77
Q

Urine bilirubin reference range

A

NEGATIVE

78
Q

Serum conj. bilirubin in

HEMOLYTIC JAUNDICE

A

normal or slightly elevated

79
Q

Serum conj. bilirubin in

INTRAHEPATIC EARLY HEPATITIS

A

Elevated

80
Q

Serum conj. bilirubin

EXTRAHEPATIC OBSTRUCTIVE

A

Significantly increased

81
Q

Serum unconj. bilirubin in

HEMOLYTIC JAUNDICE

A

Elevated

82
Q

Serum unconj. bilirubin in

INTRAHEPATIC EARLY HEPATITIS

A

Significantly increased

83
Q

Serum unconj. bilirubin in

EXTRAHEPATIC OBSTRUCTIVE

A

Elevated

84
Q

Feces urobilinogen in

HEMOLYTIC JAUNDICE

A

Elevated (+4)

85
Q

Feces urobilinogen in

INTRAHEPATIC EARLY HEPATITIS

A

Decreased (+1)

86
Q

Feces urobilinogen in

EXTRAHEPATIC OBSTRUCTIVE

A

Decreased or negative

87
Q

Urine urobilinogen in

HEMOLYTIC JAUNDICE

A

Elevated (+4)

88
Q

Urine urobilinogen in

INTRAHEPATIC EARLY HEPATITIS

A

Elevated

89
Q

Urine urobilinogen in

EXTRAHEPATIC OBSTRUCTIVE

A

Decreased or negative

90
Q

Urine bilirubin in

HEMOLYTIC JAUNDICE

A

Negative

91
Q

Urine bilirubin in

INTRAHEPATIC EARLY HEPATITIS

A

Elevated

92
Q

Urine bilirubin in

EXTRAHEPATIC OBSTRUCTIVE

A

Elevated

93
Q

1st phase of heme production

A

succinyl coenzyme A + glycine —–> aminolevulinic acid (ALA) ——> heme

94
Q

2nd phase of heme production

A

two molecules of ALA condense (via second condensation reaction) and cyclize to form porphobilinogen (PBG)

95
Q

direct precursor of porphyrinogen

A

porphobilinogen

96
Q

porphyrinogen types

A

uroporphyrinogen
coproporphyrinogen
protoporphyrinogen
protoporphyrin IX

97
Q

immediate precursor of protoporphyrin IX

A

Protoporphyrinogen IX

98
Q

Protoporphyrin IX chelates _________ to form heme.

A

iron

99
Q

porphyrins of clinical significance

A

uroporphyrin
coproporphyrin
protoporphyrin

100
Q

Types of porphyria

A

a. Plumboporphyria
b. Acute intermittent porphyria
c. Congenital erythropoietic porphyria
d. Porphyria cutanea tarda
e. Hepatoerythropoietic porphyria
f. Hereditary coproporphyria
g. Variegate porphyria
h. Erythropoietic porphyria

101
Q

Overproduction or accumulation of porphyrins and precursors, such as
porphobilinogen in the bone marrow

A

erythropoietic porphyria

102
Q

Overproduction or accumulation of porphyrins and precursors, such as
porphobilinogen in the liver

A

hepatic porphyria

103
Q

cutaneous symptoms including photosensitivity,

blisters, excess facial hair, and hyperpigmentation are caused by excess of ______.

A

later intermediates (uro, copro, protoporphyrins)

104
Q

neuropsychiatric symptoms, including abdominal pain, vomiting, constipation, tachycardia, hypertension, and psychiatric symptoms are caused by excess of _____.

A

early precursors (ALA and PBG)

105
Q

neurocutaneous

symptoms are caused by excess of _______.

A

early precursors and later intermediates (ALA, PBG and porphyrins)

106
Q

specimen required for measurement of aminolevulinic acid, porphobilinogen,
uroporphyrin, and coproporphyrin

A

24-hr urine specimen

107
Q

storage requirements for porphyrin determination

A

refrigerate

store in brown bottle (to protect light-sensitive compounds)

108
Q

porphobilinogen more stable under (alkaline/acidic) conditions.

A

alkaline

109
Q

aminolevulinic acid more stable under (alkaline/acidic) conditions

A

acidic

110
Q

used as a compromise in porphyrin determination to maintain the pH near 7

A

sodium bicarbonate

111
Q

employs p-dimethylaminobenzaldehyde reagent (also known as Ehrlich’s aldehyde reagent) to form a red condensation
product with porphobilinogen.

A

Watson-Schwartz test

112
Q

Reagent employed in Watson-Schwartz test

A

p-dimethylaminobenzaldehyde

113
Q

porphyrins appear as _________ color in long-wave ultraviolet light

A

intense orange-red

114
Q

why do porphyrins appear orange-red in color?

A

due to conjugated unsaturation of the tetrapyrrole ring structure

115
Q

What technique is used to differentiate and quantify porphyrins?

A

HPLC with a fluorescence detector system