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Flashcards in Hematology II Deck (116):
1

The Right Lymphatic Duct and the Thoracic Duct drain into what veins?

Subclavians

2

An increase in ____ or a decrease in ____ will lead to edema.

Pc

Pi-c

3

When is the Thymus largest?
What does it produce?
Located?

Puberty

WBC - especially T-lymphocytes

Mediastinum

4

Three sets of Tonsils:

Pharyngeal (adenoids)
Palatine
Lingual

5

Where is the Mucosa Associated Lymphoid Tissue (MALT)?

Mucosal epithelium of the intestine

*B and T lymphocytes

6

A defect in what will cause bleeding or thrombosis?

Hemostasis

7

From whence do platelets come?

Megakaryocytes

8

How many platelets can a single megakaryocyte produce?

3000

9

What percentage of platelets are pooled in the spleen?
What is the normal level of platelets in the blood?

20-30%

250k - 400k / mm3

10

T/F
Platelets contain granules

True

11

What is the average lifespan of a platelet?

5-20 days

12

What layer is different in veins?

Thinner tunica media

13

What is the anatomy of a capillary?

Tunica Intima only
(no media or external)

Contains endothelial cells and small amount of collagen

14

The body's first reaction to injury is the ____ phase.

Vasoconstrictive
(aka Vascular Spasm)

15

What is the vasoconstrictive phase triggered by?

Sympathetic system
direct injury itself

16

What is the precursor to a blood clot?

Platelet plug

17

What receptors on platelets bind collagen structure and form a plug?

GP1a

18

Where is von Willebrand's Factor found?

plasma
platelets
bv walls

19

What binds to von Willebbrand's Factor?

GP1b receptors

*on platelets

20

First 2 steps of platelet plug formation:

GP1a attaches to exposed collagen
Gp1b attaches to von Willebrand's Factor

21

What are the 3 platelet granules released upon adhesion?

ADP
Thromboxane A2 (prostaglandin)
Serotonin (5-HT)

22

What do ADP, TXA2, and 5-HT do once released from platelets?

Bind/recruit other platelets
Aggregate

23

What platelet receptor is responsible for aggregation of the platelet plug?
What does it bind?

GPIIb

Fibrinogen

24

Where are most clotting factors synthesized?

Liver

25

Blood clotting factors I, II, III

Fibrinogen
Prothrombin
Tissue factor/thromboplastin

26

Blood clotting factors IV, V, VII

Calcium
Proaccelerin (labile)
Proconvertin (stabile)

27

Blood clotting factors VIII, IX, X

Antihemophilic factor A/globulin

Antihemophilic factor B, Plasma thromboplastin component, Christmas factor

Stuart-Prower factor

28

Blood clotting factors XI, XII, XIII

Plasma thromboplastin antecedent, Hemophilia C, Rosenthal syndrome

Hageman factor

Fibrin stabilizing factor, Laki Lorand factor

29

What blood clotting factors are not made in the liver?
(4 factors)

III - perivascular tissue
IV - Plasma
XII - Platelets (and liver)
XIII - Platelets, plasma

30

What blood clotting factors are Vitamin K dependent?
(4 factors)

II - Prothrombin
VII - Proconvertin (stable)
IX - Ab, PTC, Xmas
X - Stuart-Prower

31

Extrinsic clotting cascade:

III - thromboplastin
IV - Ca
VII - Proconvertin
V - Proaccelerin

X - Stuart Prower

32

Intrinsic clotting cascade:

XII - Hageman
XI - Plasma thromboplastin antecedent
(aka Rosenthal, Hemophilia C)
IX - Plasma thromboplastin component
(aka Christmas, Anti-hemophilic factor B)
VIII - Anti-hemophilic factor A / Globulin

X - Stuart Prower

33

Common clotting cascade:

X - Stuart Prower
III (thromboplastin), V (proaccelirin), IV (Ca), PF3
Prothrombin Activator
II - Prothrombin > Thrombin (feedback V - proaccelirin)
I - Fibrinogen > Fibrin >
XIII - Laki Lorand (Fibrin stabilizing), Ca >
Fibrin Polymer

34

Name 3 Anti-coagulants that help to balance Hemostasis:

Thrombomodulin
Antithrombin III
Heparin cofactor II

35

How does Thrombomodulin work to shut down the coagulation pathway?

Thrombomodulin-Thrombin Complex forms
activated
Protein C and Protein S
deactivates
V and VIII

36

Which anti-coagulant is a glycoprotein produced by the liver that binds Factor X?

Antithrombin III

37

What does Heparin cofactor II inhibit?
What type of protein is it and where is it synthesized?

Thrombin

Plasma

Liver

38

What enzyme initiates the breakdown of a blood clot?

Plasmin

(from Plasminogen)

39

What converts Plasminogen to active Plasmin?
(and thus initiated Fibrinolysis)

Tissue Plasminogen Activator (t-PA)

40

What releases t-PA into the blood?

Damaged endothelium of vessels

41

Where is the Plasminogen that degrades a clot found?

In the clot

42

T/F
Plasminogen is fast acting

False

very slow to break down fibrin mesh

43

What are 2 tPA inhibitors?

Plasminogen activator inhibitor 1
Plasminogen activator inhibitor 2

44

What are 2 Plasmin inhibitors?

Alpha2-antiplasmin
Alpha2-macroglobulin

45

What is a low platelet count?
(from blood smear)

Thrombocytopenia

46

What can thrombocytopenia lead to?
(4 things)

Purpuria (purple spots)
Petechia (pinpoint hemorrhages)
nosebleeds
gum bleeds

47

Some inherited platelet disorders are associated with...

large platelets

48

What is the function of Sodium Citrate in coagulation tests?

Removes Calcium

49

What is the coagulation test for the Extrinsic Pathway?
After Calcium, what is added?
How long before clotting occurs if normal?

Prothrombin Time (PT)

Brain Thromboplastin

12-15 seconds

50

What standardizes differences in various companies coagulant factors used for testing?

What is the particular constant for a coagulant called?

International Normalized Ratio (INR)

ISI - international sensitivity index

51

When is the INR normally used?

Warfarin (coumadin) usage

52

What is the normal INR for someone using Warfarin?

2.0 - 3.0

*2.5 - 3.5 if high risk for clot formation

53

What tests the Intrinsic Pathway?

Activated Partial Thromboplastin Time (APTT)

54

In the APTT test, what is activated after Calcium?

Kaolin
Phospholipids

55

How long does clotting normally take in the APTT coagulation test?

25-36 seconds

56

What is the APTT test most often used to monitor?

Heparin

57

What tests the Common Pathway for coagulation time?

Thrombin Clotting Time (TT)

58

After Calcium what is added to the Thrombin Clotting Time test?
(common pathway test)

Thrombin

*assesses Fibrinogen > Fibrin conversion

59

When is the TT (Thrombin Clotting Time) test used?

If Prothrombin (extrinsic) or APTT (intrinsic) tests are prolonged

60

What determines actual deficiencies for specific clotting disorders?

Coagulation Factor Assays

61

If there is a prolongation of APTT test and PT is normal, what x-linked disorder might the patient have?

Hemophilia A or Hemophilia B

62

What is the prevalence of Hemophilia A?

1 in 5000 males

63

T/F
Hemophilia A is strictly genetically inherited

False

30% new mutations on VIII

64

What is mutated in Hemophilia A?

VIII (antihemophilia factor A/globullin)

65

What is mutated in Hemophilia B?
Another name?
prevalence?

IX
Christmas disease
1 in 30,000

66

What are the 4 areas of most concern in hemophiliacs?

Joint capsules
Skeletal muscles
GI tract
Brain

67

What process in joints caused hemophiliacs pain?

Healing

*breaks down bone

68

What tests will be prolonged in Von Willebrand's Disease?

APTT and PT

69

Why will PT be prolonged in Von Willebrand's disease if Factor VIII is the primary pathological concern?

Platelet adhesion is also disrupted

70

What is the most common inherited bleeding disorder?

Von Willebrand's Disease

(125 per million)

71

T/F
Von Willebrand's Disease is mild and occurs mainly in the skin

True

72

What 2 pathologies are seen in Von Willebrand's disease?

Platelet adhesion disrupted
Factor VIII

73

What can disrupt production of platelets and cause Thrombocytopenia?

Drugs
marrow failure

74

What can destroy platelets and cause Thrombocytopenia?

Idopathic thrombocytopenic purpura

*autoimmune

75

What removes platelets in ITP - Idopathic thrombocytopenic purpura?

Reticuloendothelial system

76

What conditions are associated with excessive clotting?

Thrombophilias

77

What are 4 examples of Inherited Thrombophilias?

Protein C deficiency
Protein S deficiency
Activated Protein C Resistance
Antithrombin III deficiency

78

What causes Activated Protein C resistance?

Factor V responds poorly to Protein C

*mutation in factor V Leiden gene

79

What % of North American caucasians have a Factor V Leiden Mutation?

3-8%

80

List the 4 inherited Thrombophilias in terms of prevalence?

Factor V Leiden
Protein C deficiency
Antithrombin deficiency
Protein S deficiency

81

What are the 4 main categories of drugs affecting hemostasis?

Anticoagulants
Thrombolytics (destroy clots)
Antiplatelets
Antifibrinolytics (promote clots)

82

What are the 4 main divisions of anticoagulant drugs?

Indirect thrombin inhibitors (Heparin)
Coumarin (Warfarin)
Direct Thrombin inhibitors
Direct Factor X inhibitors

83

What are the 2 most common Heparins?
(mixtures of proteins)

Unfractionated heparin (UFH) - Heparin Sodium

Low molecular weight heparin (LMWH) - Fragmin, Innohep, Lovenox

84

How is Heparin an indirect thrombin inhibitor?

Increases Antithrombin III's activity, which shuts down factor X (Stuart-Power)

Stimulates Heparin cofactor II (also inhibits thrombin)

85

T/F
UFH - unfractionated heparin can be given orally

False

Proteins are destroyed in stomach

86

Why is UFH a variable anticoagulant?

Binds many proteins in body

*individually variable

87

What test is used to monitor UFH?
What is normal?
By how much will theraputic levels of UFH prolong?

APTT
25-36 seconds
2-2.5 times normal values

88

How are Low Molecular Weight Heparins administered?
What determines dose?
Does it need to be monitored?

Subcutaneously
Body weight
No

89

How does Warfarin work?

Interferes with Vitamin K synthesis

90

What factors are dependent on Vitamin K?
(and therefore stopped by Warfarin)

II
VII
IX
X

91

T/F
Warfarin is used in prophylaxis of venous thrombosis, Pulmonary embolism, artificial heart valves, atrial fibrillation, surgery

True

92

The INR - international normalized ratio for Warfarin is...

2.0 - 3.0

93

What drugs inhibit Warfarin metabolism?
(thus accumulating warfarin and increase effects)

Cimetidine, acetaminophen, acute alcohol, antibiotics (azithromycin, cipro, clarithromycin, erythromycin)

94

What hormone can increase catabolic breakdown of clotting factors and enhance the effects of Warfarin?

Thyroid hormones

95

What drugs diminish effects of Warfarin?

Chronic alcohol
Phenytoin
Oral contraceptives

96

What food decreases the effects of Warfarin?

Vitamin K

97

T/F
Warfarin is fine during pregnancy, Heparin is not.

False

Warfarin is teratogenic - causes birth defects
Heparin is fine

98

How are Direct Thrombin Inhibitors Administered?
What is the main DTI?

Orally
Dabigatran

99

What are the advantages of Direct Thrombin Inhibitors?

non-reactive with blood proteins
Orally taken
No constant monitoring

100

What are some Direct Factor X inhibitors?

Rivaroxaban
Apixaban
Endoxaban

101

What type of drug is used in emergencies for Ischemic Strokes?

Thrombolytics

102

How do Thrombolytics work?

tPA - tissue plasminogen activator
Forms Plamin (from Plasminogen) to break down clot

103

Name 3 Thrombolytics:

Streptokinase
Urokinase
Synthetic tPA

104

Name the 3 classes of Antiplatelets.

Cyclooxygenase Inhibitors (aspirin)
Thienopyridines (ADP inhibitors)
GP IIb/IIIa inhibitors

105

How does Aspirin act as an anticoagulant?

Inhibits synthesis of TXA2
(aggregating factor)

106

How do Thienopyridines (ADP inhibitors) work?

Prevent ADP - Platelet binding
(prevents aggregation)

107

What is an ADP inhibitory drug?
(Thienopyridine)?

Clopidogrel

108

What class of drugs inhibit the "final common pathway" for platelet aggregation?
Example of drug:
How administered?

Glycoprotein IIb/IIIa inhibitors
abciximab
I.V.

109

What is an antifibrinolytic drug?

Tranexamic acid

110

How is Tranexamic Acid used in dentistry?

5% mouth rinse in pts with prolonged bleeding times

111

How does tranexamic acid work?

Prevents the formation of Plasmin by Plasminogen
(plasminogen inhibitor) by tPA

112

What is the risk of developing thromboembolism if you stop taking Warfarin for 2 days?

0.02 to 1%

113

T/F
It is safer to continue taking Warfarin throughout dental procedures and recovery.

False.

Safer to stop taking

114

What is the recommended INR before dental surgery for patients on Warfarin?

Less than 4

115

What solution is easier to make and less expensive than tranexemic acid?

Aminocaproic Acid

116

T/F
Aminocaproic Acid isn't available in Canada.

True

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