Test 4 Flashcards

1
Q

What is the most abundant trace element?

A

Iron

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2
Q

What is ferritin?

A

Storage form of iron

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3
Q

Decreased plasma ferritin is the earliest indication of what?

A

Iron deficiency

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4
Q

What does transferrin do?

A

Transports iron from GI tract to the bone marrow and other organs

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5
Q

Where is transferrin synthesized?

A

In the liver

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6
Q

Each transferrin molecule transports how many iron atoms?

A

two

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7
Q

What are some causes of increased serum iron?

A

Hemolytic anemias, thalassemias, hepatitis, excessive transfusions, iron poisoning (vitamin overdose)

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8
Q

What are some causes of decreased serum iron?

A

Insufficient dietary iron, bleeding, malabsorption, and infection or chronic disease

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9
Q

What is hemochromatosis?

A

A recessive genetic disorder where excess iron accumulates in tissues from increased GI absorption

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10
Q

What is treatment for hemochromatosis?

A

Therapeutic phlebotomy

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11
Q

What are the main steps iron tests follow?

A

Dissociate Fe from transferrin
Reduce Fe from ferric to ferrous
Add ferrozine to make a colored compound
Measure colored product by spectrophotometry

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12
Q

What specimen is needed for iron testing?

A

Serum with no hemolysis or has been in a tube with anticoagulants that bind iron (EDTA and Sodium Citrate)

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13
Q

What is the TIBC?

A

Total Iron Binding Capacity is an estimate of transferrin concentration

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14
Q

What does TIBC measure?

A

How much iron could be transported in the plasma by transferrin (not how much iron the patient has)

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15
Q

TIBC is an ________ measurement of transferrin.

A

Indirect

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16
Q

What are the steps for TIBC testing?

A
  • Add excessive amount of iron to serum to saturate transferrin.
  • Add MgCO3 to remove unbound iron
  • Centrifuge specimen to get the MgCO3 to the bottom
  • Take the supernate and test that for iron
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17
Q

What 3 components are in an iron profile?

A

Total iron, TIBC, % iron saturation

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18
Q

% Iron Saturation = ?

A

Total Iron / TIBC X 100

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19
Q

What does the % Iron saturation measure?

A

Measures how full transferrin is

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20
Q

What are the usual results for total iron, TIBC, and %Fe Sat in a person with iron deficiency?

A

Total iron decreased
TIBC increased
% Fe Sat decreased

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21
Q

What are the usual results for total iron, TIBC, and %Fe Sat in a person with hemochromatosis?

A

Total iron increased
TIBC decreased
% Fe Sat increased

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22
Q

What are the usual results for total iron, TIBC, and %Fe Sat in a person with infection/cancer?

A

Total iron decreased
TIBC decreased
% Fe Sat increased

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23
Q

What are the usual results for total iron, TIBC, and %Fe Sat in a person with hemolysis?

A

Total iron increased
TIBC normal
% Fe Sat increased

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24
Q

What is step 1 and 2 in the formation of bilirubin?

A
  1. RBCs are eaten by spleen. Hgb is catabolized into amino acids, iron, and heme
  2. Heme ring is broken open and converted to unconjugated bilirubin
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25
Q

What are steps 3 and 4 in the formation of bilirubin?

A
  1. RE cells in the spleen secrete the unconjugated bilirubin into the plasma, where bilirubin is bound by albumin.
  2. Albumin - bilirubin complex travels to liver
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26
Q

What are steps 5 and 6 in the formation of bilirubin?

A
  1. Hepatocytes conjugates bilirubin with glucoronic acid by UDPG enzyme
  2. Conjugated bilirubin is secreted into bile duct
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27
Q

What are step 7 and 8 in the formation of bilirubin?

A
  1. GI bacterial normal flora converts conjugated bilirubin into urobilinogen
  2. Urobilinogen may be excreted into stool, reabsorbed in plasma, or excreted in the urine.
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28
Q

What is UDPGs main job?

A

Conjugating bilirubin

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29
Q

What two things can increased plasma bilirubin indicate?

A

Increased RBC catabolism or decreased hepatic conjugation with excretion of bilirubin

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30
Q

What is jaundice?

A

Yellowing of the skin and sclera from increased bilirubin

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31
Q

What does icteric mean?

A

Plasma/serum with yellow color from increased bilirubin

32
Q

At what range in numbers does jaundice start showing?

A

2.5 - 3.0 mg/dL

33
Q

What causes prehepatic jaundice?

A

Excess RBC destruction or increased unconjugated bilirubin

34
Q

What causes hepatic jaundice?

A

Defective liver function
Defective hepatocyte uptake
Cholestasis (impaired hepatic transport)

35
Q

What causes post hepatic jaundice?

A

Impaired ability of liver to excrete bile into the GI tract

36
Q

What happens in Crigler - Najar syndrome?

A

Hepatocytes lack UPDG enzyme and cannot conjugate bilirubin

37
Q

What is Gilbert’s syndrome?

A

30-50% deficiency of UPDG and decreased conjugation

38
Q

What is physiological jaundice of the newborn?

A

Babies are born with immature liver and have temporary deficiency of UDPG

39
Q

What is hemolytic disease of the newborn?

A

Mother newborn blood group incompatibility

40
Q

Most common cause of HDNB?

A

O mom with A baby or rh negative mom with rh positive baby

41
Q

What happens in HDNB?

A

Maternal IgG antibodies cross the placenta and attack fetal RBCs

42
Q

What is kernicterus?

A

Permanent brain damage from excess free bilirubin penetrating blood brain barrier

43
Q

What is the total bilirubin when kernicterus occurs

A

> 20 mg/dL

44
Q

What is the treatment of HDNB

A

Uv light or exchange transfusion

45
Q

What is cirrhosis

A

Irreversible structural damage (scaring) of the liver

46
Q

What reagent is used in bilirubin techniques

A

Diazotized sulfanilic acid

47
Q

What type of bilirubin needs an accelerator?

A

Unconjugated

48
Q

What is an acid?

A

Any substance that yields a H+ in H2O

49
Q

What is a base?

A

Any substance that yields OH- in H2O

50
Q

K = ?

A

Dissociation constant

Product / reactant

51
Q

What does pK equal?

A

-log of the dissociation constant

52
Q

What is the pK?

A

Numerical expression of a substances ability to dissociate to prince H+ and OH- ions

53
Q

What is a buffer?

A

Any substance that resists change in ph

54
Q

Strong acids have a _____ dissociation constant.

A

High

55
Q

Weak acids have _____ disassociation constants.

A

Low

56
Q

What is considered acidosis in terms of pH?

A

< 7.35

57
Q

What is considered alkalosis in terms of pH?

A

> 7.45

58
Q

The most effective buffer system is?

A

The Carbonic-Acid Bicarbonate System

59
Q

What are good buffers?

A

Weak acids

60
Q

What is the Henderson-Hasselbach equation?

A

pH = pK (6.1) + log (HCO-3/H2CO3)

61
Q

What regulates H2CO3?

A

Lungs (respiratory)

62
Q

What regulates HCO3?

A

Kidneys

63
Q

The ratio of (HCO3/H2CO3) must remain at?

A

20 to 1

64
Q

What does compensation do?

A

Compensation corrects pH whenever it falls out of normal range

65
Q

What is primary compensation?

A

When one organ causes a pH problem and the “other” organ corrects it

66
Q

What is secondary compensation?

A

When the offending organ fixes its own problem

67
Q

What is respiratory acidosis?

A

Decreased respiratory activity which causes increased CO2/H2CO3 in the plasma

68
Q

What is the primary compensation for respiratory acidosis?

A

Kidneys increase H+ excretion and HCO-3 reabsorption

69
Q

What is metabolic acidosis?

A

Decreased plasma bicarbonate concentration

70
Q

What is the primary compensation for metabolic acidosis?

A

Hyperventilation - lungs decreases CO2

71
Q

What is respiratory alkalosis?

A

Decreased CO2

72
Q

Common causes of respirator alkalosis

A

Hyperventilation and aspirin overdose

73
Q

What is the primary compensation for respiratory alkalosis

A

Kidneys compensate by increasing excretion of HCO3- And increasing reabsorption of H+

74
Q

What is metabolic alkalosis?

A

Increased bicarbonate

75
Q

Primary compensation of metabolic alkalosis

A

Linda compensate by decreasing respirations and increasing carbonic acid

76
Q

What is the pH of metabolic acidosis (increased or decreased)

A

Decreased

77
Q

What is the ph for metabolic alkalosis

A

Increased