haemostasis, thrombosis and coagulation (L5) Flashcards

1
Q

What is haemostasis

A

maintain fluid flow through the vasculature

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2
Q

What is thrombosis

A

pathological, causes restriction or blockage of a blood vessel

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3
Q

What are the three stages of haemostasis

A
  1. vascular spasm
  2. Platelet plug formation
  3. coagulation
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4
Q

What is vascular spasm

A

damaged blood vessels constrict reducing blood flow in the damaged area

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5
Q

What is primary haemostasis

A

platelet activation and plug formation

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6
Q

What is secondary haemostasis

A

coagulation

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7
Q

3 critical components of platelets

A

membrane proteins
secretory granules
surface-connected open cannalicular system

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8
Q

What is the most numerous platelet secretory granule

A

Alpha granules

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9
Q

What do alpha granules contain (4)

A

Adhesive proteins
platelet-specific proteins
membrane protein
alpha granule-specific proteins

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10
Q

3 adhesive proteins of alpha granules

A

fibroinogen
fibronectin
vWF

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11
Q

3 things dense granules contain

A
vasocontructive agents (serotonin)
Platelet agonists (ADP, ATP)
Calcium and magnesium
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12
Q

What complex is important for binding vWF

A

GP2b

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13
Q

What is von willebrand factor

A

blood glycoprotein

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14
Q

What receptor id for fibrinogen and platelet aggregation (and vWF interaction)

A

GP2a3B

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15
Q

When vessel damage occurs what is exposed

A

collagen-associated (vWF on collagen`)

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16
Q

What connection is made on the platelet with the exposed vWF

A

GP1b-vWF interactions

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17
Q

How does the platelet form a stronger adhesion with the sub-endothelium

A

rolling promotes more Gb1b/ vWF associations

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18
Q

What does a stronger adhesion of platelet with sub-endothelium cause

A

platelet activation –> granule release

Conformational change—> stronger adhesion molecules

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19
Q

What platelet agonist are released after platelet activation (3)

A

ADP,
thromboxane
Fibrinogen

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20
Q

What does fibrinogen cross bridges bind to

A

GP2a3b

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21
Q

What are zymogens

A

inactive precursors of enzymes

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22
Q

Coagulation factors are a group of____

A

Zymogens

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23
Q

What the two basic pathways for coagulation

A

extrinsic

intrisic

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24
Q

how is the extrinsic pathway triggered

A

by trauma

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25
Q

how is the intrinsic pathway triggered

A

internal damage to the wall of the vessel

26
Q

What is the end product of coagulation

A

robust clot made up of fibrin which traps platelets and blood cells

27
Q

intrinsic pathway

A
12--> 12a 
11-> 11a
9->9a 
8a -d10 complex 
X--> Xa
28
Q

Extrinsic pathway

A

3
7->7a
7a-3 complex
10–>10a (Xa)

29
Q

Final common pathway

A

10a (Xa)
Prothrombin–> thrombin
Fibrinogen–>fibrin
fibrin + 13a –> cross-linked clot

30
Q

What does tissue factor pathway inhibitor (TFPI) inhibit

A

active factor 10

31
Q

What anti-coagulants stop the cascade

A

anti-thrombin

tissue factor pathway inhibitor

32
Q

2 coagulation tests

A

prothrombin time PT)

partial thromboplastin time (PTT)

33
Q

Thrombocytopenia=

A

low circulating platelets

34
Q

Most common primary thrombocytopenia

A

immune thrombocytopenia

35
Q

What antibodies coat platelets in immune thrombocytopenia

A

IgG

36
Q

Where are coated IgG platelets removed

A

splenic macrophages or kupfer cells in the liver

37
Q

What does mild immune thrombocytopenia cause

A

petechia (rash)

38
Q

Risks of severe ITP

A

extensive hematomas and cerebral haemorrhage

39
Q

What is Glanzmann’s thrombasthenia (GT)

A

autosomal recessive bleeding syndrome that affects the megakaryocyte lineage results in lack of platelet aggregation

40
Q

What specific changes happen in GT

A

changes in expression and/ or function of GP2b and/or 3a

41
Q

What is hemophilia characterized by

A

changes in clotting patterns

42
Q

What sex are most haemophillia sufferers

A

male

43
Q

What is haemophillia A a deficiency in

A

FV3

44
Q

What is haemophillia B a deficiency in

A

F9

45
Q

What does Aspirin inhibit

A

platelet cyclooxygenase (enzyme)

46
Q

What is cyclooxygenase important in

A

Thromboxane A2 generation

47
Q

Aspirin lasts____

A

life of the platelet

48
Q

Aspirin is also (2)

A

Anti-inflammatory (COX-2 inhibitor)

Anto-thrombotic (COX-1)

49
Q

use of aspirin

A

ischemic stroke
prevention and previous MI
Angina

50
Q

Side effects of aspirin

A

GI bleeding

hemorrhagic stroke

51
Q

What is clopidogrel

A

ADP antagonist

52
Q

Use of clopidogrel

A

reduce thrombotic events

53
Q

What type of drug is Clopidogrel

A

pro-drug

54
Q

Side effects of Clopidogrel

A

bleeding

Thrombotic thrombocytopenic purpura

55
Q

Warfarin=

A

vitamin K antagonist

56
Q

Warfarin in pregnancy?

A

Noooo can cross the placenta

57
Q

heparin=

A

an anticoagulant

58
Q

Two types of heparin

A

unfractionated heparin

low molecular weight heparin

59
Q

Unfractionated heparin can affect both

A

factor Xa and Thrombin

60
Q

Low molecular weight heparin can only affect

A

Factor Xa