Blood clotting Flashcards Preview

Sem 2 > Blood clotting > Flashcards

Flashcards in Blood clotting Deck (88):
1

normal intact endothelium is what kind of surface

antithrombotic

2

two potent vasodilators and inhibitors of platelet function produced by endothelium

prostacyclin, nitric oxide

3

after vascular injury there is vaso-

constriction

4

vasoconstriction after vascular injury is partly mediated by which two platelet activation products

serotonin and thromboxane A2

5

after vascular injury, blood flow is exposed to (2)

subendothelial collagen and tissue factor

6

subendothelial collagen activates

intrinsic pathway of blood coagulation

7

tissue factor activates

extrinsic pathway of blood coagulation

8

exposure to collagen activates intrinsic pathway and stimulates

platelet activation

9

platelets bind to collagen via

von willebrand factor (vWF)

10

von willebrand factor is released from

endothelial cells

11

von willebrand factor binds to collagen fibres and platelets via

platelet membrane glycoprotein receptor (GPIb-IX)

12

platelets can be activated in haemostasis by

platelet activating factor (PAF)

13

what forms initial haemostatic plug in small vessels and initial thrombus in arteries and veins

platelets

14

6 things that activate platelets

ADP, adrenaline, collagen, thrombin, PAF, high BP

15

In platelet activation, most chemicals bind and cause a change in shape from disc to

sphere

16

In platelet activation, change in shape to sphere causes

release of compounds involved in haemostasis from granules

17

Two receptors involved in platelet activation

GPIb-IX (von Willebrand Factor) and GPIIa-IIIb (fibrinogen)

18

In small vessels, blood coagulation factors interact to form secondary fibrin-rich...

haemostatic plug

19

In arteries and veins, blood coagulation factors interact to form secondary fibrin..

thrombus

20

fibrinogen is a precursor of

fibrin

21

Factor I is

fibrinogen

22

prothrombin is a precursor of

thrombin

23

Factor II is

Prothrombin

24

Factor III is (2)

Tissue factor (thromboplastin)

25

What does tissue factor activate?

Factor VII

26

Factor IV is

Calcium ion

27

Factor V is

Proaccelerin/ labile factor

28

2 actions of factor V

activates factor VII, combines with factor X to form prothrombin activator

29

Factor VII is also known as (2)

stable factor, serum prothrombin conversion accelerator

30

action of factor VII

activates factor X - EXTRINSIC PATHWAY

31

Factor VIII also known as

antihaemophilic factor

32

activity of factor VIII

activates factor X - INTRINSIC PATHWAY

33

Factor IX action

activates factor VIII

34

Factor X action

combines with factor V to form prothrombin activator

35

Factor XI action

activates factor IX

36

Factor XII action (3)

activates factorXI and plasmin, converts prekallikrein to kallikrein

37

Factor XIII also known as

fibrin-stabilising factor

38

Factor XIII action

cross linking of fibrin fillaments --> fibrin polymer = stabilises clot

39

role of platelet factor 1 (3)

activates factor VII, combines with factor X to form prothrombin activator, accelerates platelet activation

40

role of platelet factor 2

accelerates thrombin formation

41

role of platelet factor 3 (2)

aids in activation of factor VIII and prothrombin activator

42

role of platelet factor 4

bind heparin during clotting --> inhibit anticoagulant effect

43

3 pathways of blood clotting

extrinsic, intrinsic, common

44

3 lab tests for coagulation

thrombin time, prothrombin time, activated partial thromboplastin time (APTT)

45

Intrinsic pathway only uses clotting factors found in

blood

46

Which lab test is used to test intrinsic pathway

APTT (activated partial thromboplastin time)

47

Intrinsic pathway of coagulation

Platelets degranulate > release factor XII > Factor XI activated > Factor IX activated > calcium ion, PF3 and Factor IX activate Factor VIII > Factor X

48

Extrinsic pathway initiated by clotting factors from sources other than blood released by

damaged blood vessels and perivascular tissues

49

Extrinsic pathway of coagulation

tissue factor > combines with factor VII and calcium ion > activates factors IX and X > greatly accelerates coagulation

50

tissue factor is expressed in all cells other than

endothelial cells

51

clinical test for extrinsic pathway of coagulation

prothrombin time (PT)

52

damaged blood vessels and perivascular tissues release

tissue factor

53

final common pathway of coagulation is tested for by

Thrombin time (TT)

54

final common pathway of coagulation

Factor Xa (from extrinsic or intrinsic) combines with Factor III and V in presence of calcium ion and PF3 > prothrombin activator > acts of factor II > converts to thrombin > chops factor I (fibrinogen) to fibrin > combines with Factor XIII (fibrin stabilising factor) and calcium ion > fibrin polymer

55

fibrin polymer forms structural framework of

blood clot

56

in common pathway, thrombin works with factor V to accelerate production of

prothrombin activator

57

tissue repair is achieved by (2)

clot retraction and damage repair

58

process of clot retraction

after clot formation, platelets adhere to strands of fibrin > fibrin threads pulled > edges of broken vessel pulled together > clot compacts

59

process of damage repair

platelets and endothelial cells secrete platelet derived growth factor (PDGF) > stimulates fibroblasts and smooth muscle cells to multiply > repair damaged blood vessel > fibroblasts invade clot > produce fibrous connective tissue > helps strengthen and seal vessel whilst repair takes place

60

kallikrein action

converts plasminogen to plasmin (a fibrin dissolving enzyme)

61

factor XII catalyses formation of

kallikrein

62

thrombin activates

plasmin

63

most common hereditary clotting disorder

factor V leiden

64

deep vein thrombosis is part of group of problems together known as

venous thromboembolism

65

DVT affects how many /1000 people in UK every year

1/1000

66

3 symptoms of DVT

pain/tenderness of calf, swelling of calf, colour/temperature change of calf

67

risk factors /causes of DVT(12)

dehydration (sticky blood), male, obesity, pregnancy, over 60yrs old, contraceptive pill/ HRT, cancer, heart failure, conditions that cause thrombophilia, damage to inside lining of vein, immobility, spontaneous DVT

68

way of calculating likelihood of DVT (and PE)

Well's score

69

NICE recommended Well's scale is how many levels

2

70

Well's scale for DVT from .... to ....

-2 to 9

71

score on Well's scale meaning unlikely DVT

less that 2

72

score on Well's scale meaning likely DVT

2 or more

73

Well's scale for PE from ... to ...

0 to 12.5

74

Score on Well's scale meaning unlikely PE

4 or less

75

Score on Well's scale meaning likely PE

more than 4

76

D-Dimer test detects

pieces of blood clot that have been broken down and lost in bloodstream

77

D Dimer test isn't always reliable as can increase after (4)

operation, injury, inflammation, pregnancy

78

additional tests to Well's scale assessment needed to confirm DVT such as (2)

ultrasound, venogram

79

4 treatments for DVT

anticoagulation, compressive stockings, regular walking, raising leg when resting

80

2 causes of PE

DVT, embolus which is not clot

81

symptoms of PE (6)

breathlessness, coughing up blood, fever, tachycardia, chest pain, feeling faint

82

treatment for PE (6)

anticoagulants, oxygen, IV fluids, surgery, filters, thrombolysis

83

vitamin K has two types

vitamin K1, vitamin K2

84

vitamin K1 is found in

leafy green vegetables

85

vitamin K2

main storage form in animals

86

what is vitamin K required for? (4)

post-translational modification of certain proteins required for blood coagulation, metabolic pathways, bone, other tissues.

87

what in colon convert vitamin K1 > vitamin K2

bacteria

88

risk factors of blood clot formation (11)

obesity, pregnancy, immobility, smoking, over 60 yrs, diabetes, high BP, high cholesterol, trauma, oral contraceptives, inherited clotting disorders