Primary & Secondary Haemostasis Flashcards

1
Q

How long does Primary Haemostasis lasts in humans?

A

10 days

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2
Q

Describe the structure of platelets?

A

Non- nuncleated biconvex disc

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3
Q

Where are platelets produced?

A

In the bone marrow by fragmentation of the cytoplasm of megakaryocytes

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4
Q

What is the main regulator of platelet formation ?

A

Thrombopoetin

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5
Q

Where is thrombropoetin produced?

A

In the liver

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6
Q

What is Haemostatsis?

A

It is the cessation of blood flow through a blood vessel or body tissue and is the physiologic end point after injury to a vessel wall or tissue.

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7
Q

Which substances are natural inhibitors of platelet aggregation?

A

Nitric Oxide
Prostacyclin (PGI2)
ADP dephosphotases (CD39 - Ectonucleotidase)
They act as vasodilators

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8
Q

Where are the natural inhibitors of platelet aggregation produced?

A

By endothelial cells

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9
Q

What is the normal size of platelets?

A

2-3 microns

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10
Q

What is the lifespan of platelets?

A

8-10 days

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11
Q

What is the normal platelet count?

A

250 × 109/L (range 150–400 × 109/L)

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12
Q

What is the name of the molecule that accommodates Antithrombin III?

A

Heparin Sulfate (Heparin)

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13
Q

What is the purpose of antithrombin III?

A

It is a serine protease inhibitors, ( it inhibits all coagulation proteins)
It inhibits Factor IIa, VIIa, IXa, Xa, XIa , XIIa and kalikrein

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14
Q

What is the purpose of Heparin?

A

It allows antithrombin III to bind to it and significantly increases its anticoagulant activity against factor IIa

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15
Q

What protein is activated by thrombomodulin?

A

Protein C

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16
Q

What is the purpose of Protein C?

A

Protein C is a vitamin K dependent molecule which INACTIVATES factors V and VIII by DECREASING the production of thrombin.

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17
Q

What is the purpose of Tissue plasminogen activator (tPA) found on endothelial cells?

A

Tissue plasminogen activator (tPA) activates PLASMINOGEN which then produces PLASMIN. Plasmin is a “fibrin cutter” it degrades fibrin into fibrin degradation products (FDP’s ) and also insoluble fibrin monomers called D-dimers”

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18
Q

Where is Plasminogen produced?

A

In the liver

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19
Q

Where are Von Willibrand factors stored?

A

Weibel–Palade bodies and platelet α granules,

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20
Q

Where are Von Willibrand factors (vWF) synthesised?

A

By endothelial cells and Megakaryocytes

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21
Q

True or False? vWF also circulates in the plasma bound to factor VIII, acting as a stabilizer for factor VIII.

A

TRUE!!

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22
Q

What is the function of Thrombin A2?

A

It serves as a vasoconstrictior and a platelet aggregator

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23
Q

What substance released from dense granules has a major positive feedback role in promoting platelet activation?

A

ADP

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24
Q

True or false?TXA2 increases platelet cyclic adenosine monophosphate (cAMP) levels ?

A

FALSE!! TXA2 DECREASES platelet cyclic denosine monophosphate (cAMP) levels

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25
Q

What enzyme does Aspirin inhibit?

A

Cyclooxygenase

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26
Q

Describe the role of Aspirin in platelet aggregation.

A

Aspirin irreversibly inhibits the platelet cyclooxygenase (COX) enzyme, thereby halting production of TXA2. Platelet count will remain normal in these patients.

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27
Q

What are the substances contained in Dense ( Delta ) granules?

A

S- Serotonin
A- ADP
C - Calcium
“That is one Dense SAC”

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28
Q

What is the function of Serotonin ?

A

Serotonin serves as a vasoconstrictor

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29
Q

What is the function of ADP?

A

ADP serves as a platelet aggregator. ADP interact with the ADP receptor found on platelets and initiates a cascade that promotes the insertion of glycoprotein IIb/IIIa receptors on the platelet surface.

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30
Q

What is the function of Calcium?

A

Allows coagulation factors to aggregate with platelets also- it helps to cross-link adjacent platelets.

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31
Q

What factor does factor XIIa activate?

A

Factor XIa(11)

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32
Q

Factor XIa activate?

A

Factor IX (9)

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33
Q

What is another name for Factor IX ?

A

Christmas Factor

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34
Q

What is another name for factor XII?

A

Haegman factor

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35
Q

What is the anticoagulation cascade initiated by?

A

By FXIIa via the activation of Plasminogen and Kininogen system

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36
Q

What is the Kininogen system?

A

The kininogen system produces kallikrein and bradykinin. Kallikrein activates the fibrinolytic system and promotes the activation of plasminogen into plasmin, whereas bradykinin acts as part of the body’s inflammatory response to increase vasodilation, vessel permeability, and pain.

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37
Q

Where is pro-thrombin(Factor II) produced?

A

In the liver

38
Q

What are the Vitamin-K dependent proteins?

A

Factors II, VII IX ,X , Protein C and S.

There is two(II) many seven day weeks (VII) . It should be nine and ten (IX and X) day weeks so that I can see(C) Shells (S)

39
Q

What substances do Thrombin stimulate in the Coagulation cascade?

A

Thrombin stimulates Thrombin stabiliizng factor ( aka Factor XIII (13) ) Factor 13 promotes the cross linking of insoluble fibrin monomers.

40
Q

What is another name for Tissue factor?

A

Factor III

41
Q

What is another name for activated factor II (F-IIa)?

A

Thrombin

42
Q

What other substances must Factor X be associated with to activate Prothrombin?

A

Phospholipds, Factor V, Calcium
remember 1/2 of 10 is 5(V)

43
Q

What other sustances must Factor IX be associated with inorder to activate factor number X in the Intrinsic pathway?

A

Phospholipids, Calcium , Factor VIII(8)

44
Q

What is the function of the fibrinolytic systems?

A

They help to degrade clots

45
Q

What factors are degraded by Plasmin?

A

Factors I,V and VIII

46
Q

What are some activators of Plasminogen?

A
  1. tPA
    2.Hageman factor(Factor XIIa)
    3.Urokinase
    4.Streptokinase
47
Q

What is an Activator of Plasminogen?

A

Aminocarproic acid

48
Q

What Glycoprotein is deficient in a patient with Bernard–Soulier syndrome?

A

Glycoprotein Ib

49
Q

A deficiency of Glycoprotein IIb/IIIa (aka αIIb and β3) is present in which disease?

A

Glanzmann’s thrombasthenia/ disease

50
Q

True or False? TPO decreases the number and rate of maturation of megakaryocytes via c‐MPL receptor

A

FALSE!! It INCREASES it .

51
Q

What proteins detect the platelet count in ones body?

A

1.Apoptotic BAX
2.Anti‐apoptotic BCL‐2 proteins in the cell

52
Q

What do Alpha granules contain?

A

Vans-Von- Willebrand factor
Containing -Clotting factors
Platelets-Platelet derived Growth factors

” Vans containing platelets”

53
Q

True or False? Platelets express ABO and HLA class I and II antigens?

A

FALSE, Platelets express ABO and HLA class I but NOT class II antigens.

54
Q

In the formation of Thromboxane (TXA2 ), cycoloxygenase is involved in which of the following actions?

A

Arachadonic acid to Endoperioxidase ( PGG2 &PGH2)

55
Q

What enzyme converts phospholipids to Arachodonic acid?

A

Phospholipase

56
Q

In the formation of Thromboxane (TXA2 ), thromboxane synthase is involved in what process?

A

Endoperioxidase ( PGG2 and PGH2) to Thromboxane A2

57
Q

Which enzyme converts cAMP to AMP in the synthesis of TXA2?

A

Phosphodiesterase

58
Q

What is the function of Platelet Derived Growth Factor(PDGF)?

A

PDGF found in the α granules of platelets stimulates vascular smooth muscle cells to multiply and this may hasten vascular healing following injury.

59
Q

What is another name for Factor 1?

A

Fibrinogen

60
Q

Which two main factors are Cofactors?

A

Factor V ( Labile factor)
Factor VIII ( Antihaemophilic factor)

61
Q

True or False? Bleeding time is used to test platelet dysfunction?

A

FALSE!! It is used to test platelet function.

62
Q

What is Partial thromboplastin time (PTT )?

A

PTT is used to assess the function of the INTRINISIC pathway and to follow heparin therapy.

63
Q

What is Prothrombin time( PT)?

A

PT is used to assess the function of the EXTRINSIC pathway and to follow warfarin

64
Q

What is a normal PT range?

A

11-15 seconds

65
Q

What is normal PTT range ?

A

25-40 seconds

66
Q

Which test measures factors VIII, IX, XI and XII in addition to factors X, V, prothrombin and fibrinogen?

A

The activated partial thromboplastin time (APTT)

67
Q

Which does not contain clotting factors? Plasma or Serum?

A

Serum DOES NOT contain clothing fators

68
Q

What is another name for Thrombin?

A

Factor II

69
Q

What is the name of the substance that is produced when the endothelial lining is damaged and what is its function?

A

Endothelia - It causes contraction of the smooth muscle causing Vasoconstriction ( in an effort to prevent blood loss).

70
Q

What are the different types of mechanisms that are involved with Vascular spasm?

A

Endothelin - when endothelial cells are damaged they produce Endothelin that causes smooth muscle contraction leading to vasoconstrictor.’

Myogenic mechanism - When the smooth muscle is directly injured this mechanism will cause contraction.

Noicioceptor activation- These receptors stimulate pain that will initiate smooth muscle contraction.

71
Q

How is Factor XII stimulated in Secondary Haemostatsis?

A
  • FXII can autoactivate when it comes into contact with a negatively charged surface, such as a glass tube or exposed collagen from a damaged blood vessel.

*The activation of FXII is also facilitated by circulating high-molecular-weight kininogen (HMWK) in this setting.

72
Q

True or False? Factor XIIa can only stimulate the coagulation cascade?

A

FALSE!! It can stimulate both Coagulation and Anticoagulant cascade.

73
Q

What is another name for Factor XII?

A

Haegman Factor

74
Q

What is another name for Factor X?

A

Stuart Factor
“ Stuart is 10 “

75
Q

Proaccelerin is also known as ?

A

Factor V

76
Q

What is known as Factor XI?

A

Plasma Thromboplastin Antecedent (PTA)
“ I never went to PTA meetings in grade 11”

77
Q

What is ACTIVATED factor II known as?

A

Thrombin

78
Q

What is another name for Factor II?

A

Prothrombin

79
Q

What substance is known as Factor 1?

A

Fibrinogen

80
Q

What factors does Plasmin degrade?

A

I, V, and VIII

81
Q

What substances are activators of Plasminogen?

A

tPA
Hageman factor(XIIA)
Urokinase
Streptokinase

82
Q

What is the name of the factor that helps to regenerate the endothelial lining after damage?

A

VGEF - Vascular- Endothelial Growth Factor

83
Q

Haemophilia A is a disorder in a deficiency of what factor?

A

Factor VIII( Antihaemophillic Factor)

84
Q

A deficiency in Factor XI( PTA) will cause what disease?

A

Haemophilia C

85
Q

A deficiency in what factor causes Haemophilia B?

A

Factor IX (Christmas Factor)

86
Q

Fill in the blanks. “Haemophilia A & B are _____ .”

A

X-linked recessive

87
Q

What is used to detect normal platelet function?

A

Bleeding time(BT) Normal 2-7 mins

88
Q

True or False? In Haemophilia there’s is a INCREASED PTT and a normal PT.

A

TRUE!!

89
Q

What would be the laboratory findings with Liver disease?

A

Elevated PT,PTT& BT

90
Q

What are Hereditary Thrombosis syndromes that lead to Hypercoagibility ?

A

Anti- Thrombin deficiency - no antithrombin - more prone to clotting.

Factor V Leiden - Mutation in Factor V that doesn’t allow it to be inactivated by Protein C so more coagulation more clots.

Protein C or S deficiency - won’t stop coagulation since there’s none. Increased activity in factor 5 & 8