Antiplatelets and Anticoagulants Flashcards

1
Q

what is haemostasis?

A

the arrest of blood loss from a damaged vessel

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2
Q

what is exposed when the vascular wall is damaged?

A

collagen

tissue factor (TF)

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3
Q

what is involved in primary haemostasis?

A

local vasoconstriction

adhesion, aggregation and activation of platelets

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4
Q

what do platelets do when activated?

A

extend pseudopods

release thromboxane A2

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5
Q

what is TXA2?

A

thromboxane A2

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6
Q

what does TXA2 cause?

A

mediator release

vasoconstriction

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7
Q

what mediators are released in response to TXA2?

A

serotonin

ADP

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8
Q

what does ADP do?

A

activates further platelets

aggregates platelets into a soft plug

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9
Q

what is the key event in the coagulation cascade?

A

production of thrombin, that cleaves fibrinogen to fibrin

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10
Q

what is factor IIa?

A

protease thrombin

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11
Q

what does thrombindo?

A

cleaves fibrinogen to fibrin

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12
Q

what does fibrin do?

A

forms a solid clot

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13
Q

what is inactivated factor X converted to, and what is involved in this process?

A

converted to active factor Xa by tenase

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14
Q

what is prothrombin converted to?

A

thrombin by prothrombinase

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15
Q

what is inactive factor II?

A

prothrombin

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16
Q

what is thrombosis?

A

pathological haemostasis

17
Q

what are the predisposing factors for thrombosis?

A

virchow’s triad

  1. vessel wall injury
  2. abnormal blood flow
  3. increased coagulability of blood
18
Q

what colour is an arterial thrombus and why?

A

white

mainly made of platelets in a fibrin mesh

19
Q

where is an arterial embolus likely to lodge?

A

in an artery

20
Q

what is used to treat an arterial thrombus?

A

antiplatelet drugs

21
Q

what colour is a venous thrombus and why?

A

red

it is fibrin rich

22
Q

where is a venous embolus likely to lodge?

A

the lungs

23
Q

what is used to treat a venous thrombus?

A

anticoagulants

24
Q

what part of the coagulation cascade is targeted by rivaroxaban?

A

factor Xa is inhibited

25
Q

what part of the coagulation cascade is targeted by heparin and LMWH’s?

A

factor Xa is inhibited, via antithrombin III

26
Q

what part of the coagulation cascade is targeted by warfarin?

A

necessary modification of factors X and II are blocked

27
Q

what part of the coagulation cascade is targeted by dabigatran?

A

factor IIa is inhibited directly