haemostasis Flashcards

1
Q

haemostatic mechanisms

A

platelet plug
vasoconstriction
coagulation

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2
Q

thrombin converts..

A

fibringogen into fibrin

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3
Q

Why does bernard-soulier syndrome cause bleeding?

A

platelets do not adhere

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4
Q

clotting factor activation dependent on

A

carboxylation of glutamate

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5
Q

factor 5 Leiden mutation causes what genetic disorder?

A

hypercoagulability disorder

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6
Q

vitamin K reduction required for activation of which enzyme?

A

gamma glutamyl carboxylase

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7
Q

reduced vitamin K acts as a …?

A

co factor

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8
Q

why are newborns injected with vitamin K

A

cannot synthesize K2

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9
Q

why can bile acids not be taken with anti-coagulants?

A

bile acids needed for vitamin K absorption
hemorrhage

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10
Q

warfarin background:

A

oral
derived from coumarin
delayed onset
long half life
narrow therapeutic range

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11
Q

how does warfarin lower hydroquonione ?

A

inhibits VKORC1 which converts expoxide into quinione and then to hydroquinione

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12
Q

warfain uses:

A

DVT and pulmonary emvolism

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13
Q

how does warfarin reduce the availability of hydroquinione

A

similar structure to vitamin K competitive inhibition of VKORC1

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14
Q

at which level does warfarin cause inhibiton?

A

inhibits vitamin K epoxide reductase

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15
Q

heparin enhances the activity of which molecule….

A

antithrombin

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16
Q

by enhancing the effect of antithrombin, which molecules are inhibited by heparin?

A

clotting factor 10a
thrombin

17
Q

limitation of heparin:

A

no effect on thrombus-bound thrombin

18
Q

half life of heparin vs warfarin

A

heparin shorter half life

19
Q

heparin can cause a decrease in circulating….

A

platelet numbers

20
Q

types of direct thrombin inhibitors:

A

bivalent and univalent

21
Q

DTIS inhibit…

A

coagulation and platelet activation

22
Q

warfarin and heparin differ to direct thrombin inhibitors in what way?

A

direct thrombin inhibitors do not have an active site

23
Q

downside of rivaroxban:

24
Q

effect of antiplatelet drugs:

A

decrease platelet activation and thrombus formation

25
difference between arterial and venous thrombi:
platelets in a fibrin mesh are found in arterial circulation
26
which drugs have anti-platlelet properties?
NSAIDS and SSRIs
27
3 classes of antiplatlet drugs:
COX1 inhibitors ADP receptor antagonists glycoprotein IIb-IIIa antagonists
28
thromboxane 2 role...
enhances platelet activation
29
arachidonic acid is the precusor of what molecule....
prostaglandins via COX enzymes
30
thromboxane is derived from what molecule?
prostaglandin
31
aspirin inhibits the production of what thromboxane precursor?
prostaglandins
32
thromboylsis definition
drug induced clot breakdown
33
what processes do thrombolytic agents enhance?
fibrinolysis via stimulating plasmin production
34
what is the only drug which breaks down clots?
thrombolytic agents
35
function of antifibrinlytic agents
reduce the conversion of plasminogen to plasmin
36
how do bivalent and univalent direct thrombin inhibitors differ?
bivalent bind to two active sites