Hemostasis Flashcards Preview

Hematology > Hemostasis > Flashcards

Flashcards in Hemostasis Deck (100):
1

What is the protein that is activated by the coagulation cascade?

thrombin

2

What is the function of thrombin?

Cleaves fibrinogen into fibrin

3

What is the protein found on platelets that interacts with vWF?

Glycoprotein Ib

4

What is the glycoprotein on platelets that serves as the attachment point for other platelets?

Gp IIa/IIIb

5

What is the role of factor VIII?

Binds to vWF, and promotes coag

6

What is integrin Alpha2Beta1?

Receptor on the surface of platelets, that binds to collagen

7

What happens to platelets as they bind to vWF? What is the signal for this?

undergo a shape change (disc to sphere) in response to Ca

8

What are the two granules that platelets secrete?

Alpha
Delta (dense)

9

What are the chemicals found in delta granules? (6)

ADP
ATP
Ca
Histamine
5HT
Epi

10

What are the chemical found in alpha granules?

Fibrinogen
Fibronectin
vWF
factor V

11

Activation of platelets causes the release of what precursor molecule for protaglandins?

Arachidonic acid

12

What is the enzyme that converts arachidonic acid into prostaglandin G2?

COX

13

What does prostaglandin g2 get turned into? What next?

Prostaglandin H2, then into thromboxane A2 via thromboxane synthase

14

What is the enzyme that converts prostaglandin H2 into thromboxane A2?

Thromboxane synthase

15

Thromboxane, 5HT, and epi serve to do what to blood vessels?

vasoconstriction

16

What are the two major aggregation signals for platelets?

ADP
Thromboxane A2

17

What is the MOA of ADP increasing aggregation of platelets?

conformation change of GpIIb/IIIa, allowing fibrinogen to attache

18

What is von Willebrand disease?

decrease in vWF protein levels, function, and a decrease in factor VIII binding

19

What is the most common bleeding disorder?

vWF disease

20

What are the symptoms of von Willebrand disease?

Excessive bleeding and easy bruising/bleeding that presents in early childhood

21

What is the treatment for von Willebrand disease? MOA?

Desmopressin--stimulates the release of vWF and factor VIII

22

What is Bernard-Soulier syndrome?

Giant platelet secretion/thrombocytopenia, and defect in the interaction of gpIb and vWF


Causes an inability of platelet to adhere correctly

23

What is the treatment for Bernard-Soulier syndrome?

minimize bleeding risk

24

What is Glanzmann thrombasthenia?

Quantitative/qualitative defects in GpIIb/IIIa

Prolonged bleeding time d/t reduction in platelet aggregation

25

Defect in GpIb/vWF = what disease?

Bernard-Souilier

26

Defect in GP IIa/IIIb results i what disease?

glanzmann thrombasthenia

27

Decreased vWF = what disease?

von Willebrand disease

28

What is the convergence point of the coagulation cascades?

factor X

29

Why is the extrinsic pathway named as such?

Exogenous material (tissue factor) was needed to activate it

30

Which pathway is activated upon exposure to negatively charged surfaces?

intrinsic pathway

31

What are zymogens?

inactive precursors of proteins

32

factor I = ? Where is it produced?

Fibrinogen, liver

33

factor II = ? Where is it produced?

Prothrombin

Liver

34

factor III = ? Where is it produced?

Tissue factor
Most everywhere

35

factor VI = ? Where is it produced?

Ca

36

factor V= ? Where is it produced?

Proaccelerin

Liver

37

factor VI = ? Where is it produced?

no such thing

38

factor VII = ? Where is it produced?

Proconvetrin

39

What are the factors that need vit k to function? What is the molecule that they all have in common that needs vit K?

10, 9, 7, 2
gamma carboxyglutamate

40

What is the enzyme that requires vitamin K as a cofactor?

Carboxylase

41

What is endothelin, and what does it do?

Local factor produced by endothelial cells that causes vasoconstriction

42

What is the cement part of the clot?

Fibrin

43

Do platelets have RNA?

Small amount

44

What is the mineral that is secreted by platelets that causes activation of the coag cascade?

Ca

45

What is the cytokine that triggers the change in conformation of GpIIb/IIIa to allow for the receptor to bind to fibrinogen?

ADP

46

What is the basis of the partial thromboplastin time test?

Intrinsic pathway will clot with exposure to negative charges on glass

47

What is the purpose of the gamma carboxyglutamate on factors 10, 9, 7, and 2?

Chelates Ca a lot better than glutamate does, allowing for Ca ions to coordinate negatively charged lipid membranes and keeping them bound

48

What is the enzyme that is inhibited by warfarin? What does this do?

Vitamin K epoxide reductase, prevents Vitamin K from being reduced back to its usable form

49

What type of molecule is factor 7? What does it do?

Serine protease that cleaves factor X, another serine protease

50

What type of molecule is factor 10?

Serine protease

51

factor Xa catalyzes the slow or fast cleavage of prothrombin?

Slow

52

What type of molecule is factor X? What is its function?

Serine protease, that cleaves factor V

53

What are the two components of the prothrombinase complex? What does this do?

Factors V and X
cleaves prothrombin rapidly

54

What are the three major functions of thrombin?

1. Cleave fibrinogen
2. activates factor V and VII (positive feedback
3. Activate factor VIII (intrinsic pathway)

55

What is the test that is used to assess the intrinsic pathway?

PTT

56

What is the first factor that is activated in the intrinsic pathway? How?

Factor XII by exposure to negatively charged surfaces

57

What are the two factors that factor XII activates? What is this factor complexed with?

Factor XI, which is complexed with prekallikrein to form a high molecular weight kininogen (HMWK)

58

What is the factor that factor XI activates?

factor IX

59

What is the factor that factor IX activates? Is this a fast or slow reaction?

factor X, slow

60

Thrombin cleaves what factor

VIII

61

What are the factors that form the intrinsic tenase complex? What is the function of this complex?

VIII, IX.

Rapid activation of factor X

62

What is the factor that must be activated to form the hard clot? What type of molecule is this?

XIII
transglutaminase

63

What is the amino acid bond that factor XIII catalyzes in fibrin?

K to a E

64

What is the mode of inheritance for hemophilia A and B?

xLR

65

What is the most common hemophilia?

A

66

What is the pathophysiology of hemophilia A?

deficiency of factor 8 production

67

What is the pathophysiology of hemophilia B?

Deficiency of factor IX production

68

What is the treatment for hemophilia A and B?

Recombinant factor (8 or 9 for A and B respectively)

69

How does thrombin inhibit clotting?

when thrombin is bound to a membrane protein of endothelial cells referred to as thrombomodulin, the specificity of thrombin is altered. Rather than promoting clotting, thrombin instead converts a protein C, which is a serine protease, into its active form

70

What type of molecule is protein C? What does it do?

Serine protease.

Binds to protein S, which degrades factor Va and VIIIa

71

What is the function of protein S?

Binds to protein C, which degrades factors V and VIII

72

What are the factors that the protein S/C complex degrades?

V and VIII

73

What is the molecule that thrombin binds to, to activate protein C?

thrombomodulin

74

What are the serpins?

Serine protease Inhibitors

75

What type of molecules is antithrombin III? How does it work?

Serpin (serine protease inhibitor)

Binds and inhibits thrombin, factors IX, X, XI, and XIII

76

The formation of antithrombin III is greatly enhanced by the presence of what chemical? How does this work?

Heparin binds to ATIII, and increases its affinity for thrombin

77

What is the function of the TFPI protein?

produced by endothelial cells, and inhibits factor VII and Xa

78

What is the pathophysiology of factor V leiden?

AA change leads to resistance to cleavage by protein C

79

What is the process that down regulates coagulation factors?

Fibrinolysis

80

What is the molecule that is responsible for fibrinolysis?

Plasmin

81

What is the circulating form of plasmin? What organ produces this?

Plasminogen--liver

82

Plasminogen has a high affinity for what molecule? What happen when it binds to this?

fibrin-- gets incorporated into the developing clot

83

What is the molecule that activates plasminogen into plasmin? What cells produce this?

tPA produced by endothelial cells

84

Release of tPA is stimulated by what molecule? What else does this do to ensure that tPA is activated?

Protein C

Also degrades PAI-1 (which inhibits tPA)

85

What is the function of PAI-1?

Inhibits tPA

86

tPA has a high affinity for what molecule? Why is this important?

Fibrin

Goes to where plasminogen is

87

What are the circulating proteins in the blood that ensure active plasmin does not break down clots throughout the body?

alpha2-antiplasmin
alpha2-macroglobulin

88

What is the function of streptokinase?

Exogenous activator of plasminogen

89

What does ADP trigger on platelets?

Conformation change of GP IIb/IIIa, allowing to bind fibrinogen

90

Why do platelets fail to aggregate in bernard soulier syndrome?

Defect in the Gp-Ib

91

Why do platelets fail to aggregate in Glanzmann thrombasthenia?

Defect in GpIIb/IIIa

92

What do you add to the PT test to initiate the extrinsic pathway?

Tissue factor

93

What is the only factor that is not produced by the liver? What is it produced by?

Factor VIII

Endothelial cells

94

What is the function of the Ca that binds to gamma-carboxyglutamate?

Chelates Ca on phospholipids, keeping the factors near the site they're needed

95

Why are neonates given a Vit K shot?

Vit K produced by gut flora, of which neonates have none

96

What are the components of the extrinsic Xase complex?

Factors VII and X

97

What is the factor that factor X activates to generate the extrinsic pathway tenase complex?

Factor V

98

What is the initial complex of proteins that sets off the intrinsic pathway? What is this called? What activates it?

Factor XI, prekallikrein, forming the HMWK

Carboxypeptidase on cell membrane activates it

99

What is the effect of factor XIII?

Activated by thrombin
Will crosslink E and K residues on platelets

100

What are the two factors that are inhibited by protein S?

8 and 5