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Flashcards in Biochem Deck (45)
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1

activation of extrinsic vs intrinsic

extrinsic : external trauma
intrinsic: trauma inside the vascular system

2

extrinsic pathway is mediated by factors

VII

3

intrinsic pathway is mediated by

factors XII, XI, IX, VIII

4

extrinsic and intrinsic pathways converge at factor

X

5

factor IIa is also known as

thrombin (II is prothrombin)

6

main function of thrombin

converts fibrinogen to fibrin

7

primary vs secondary hemostasis

primary = weak platelet plug
secondary = stronger reinforced by fibrin clot

8

thrombin is essential to which level of hemostasis

secondary hemostasis

9

major actions of thrombin besides conversion of fibrinogen to fibrin (4)

activate factor XIII (cross-links fibrin)
Self-activation
activation of platelets
Activates factor V and VIII

10

function of factor XIII

cross links fibrin, activated by thrombin

11

MoA of anticoagulants like warfarin

Vitamin K inhibition (epoxide hydrolase) - prevents formation of the gamma-carboxyglutamate AA utilized in Factors II, VII, IX, X and proteins S and C

12

Coagulation factors that contain gamma-carboxyglutamate AA

Factors II, VII, IX, X and proteins S and C

13

which form of vitamin k is active form

quinol form in the liver

14

why do patients with liver disease tend to have issues with hemostasis

cannot form coagulation factors (II, VII, IX, X and proteins S and C) that are formed in the liver

15

primary reversal agent for warfarin

vitamin k

16

warfarin inhibits the enzymes

vitamin k 2,3-epoxide reductase and vitamnin K quinone reductase

17

vitamin K quinone converted to quinol by what enzyme

vitamin K quinone reductase

18

genetic protein C deficiency causes

significantly increased risk of venous thrombosis because it plays a role in inactivate factor Va and VIIa (intrinsic factors) and therefore limits thrombin formation
common mutation

19

hemophilia a is a deficiency in what

factor VIII

20

hemophilia b is a deficiency in what

factor IX

21

hemophilia is a defect in what pathway

intrinsic pathway

22

in the extrinsic pathway, what activates factor VII

Tissue factor (thromboplastin)

23

PT evaluates

extrinsic factors

24

PTT evaluates

intrinsic factors and common clotting pathways

25

PT is always _____ than PTT

faster

26

PT: prolonged
PTT: normal
===

liver diseasd: decreased vitamin K, decreased factor VII (or defective) chronic low grade disseminated intravascular coagulation (AC drug warfarin therapy)

27

why is there a 48 hour interval between discontinuing warfarin therapy and establishing a normal PT?

time required for activation of coagulation pathway

28

if a patient presents with a stroke, what is the most appropriate immediate treatment

facilitation of the conversion of plasminogen to plasmin (this is the mechanism of action of thromobolytics, which are used to treat strokes)
warfarin has a slower action
plasmin breaks down fibrin

29

a deficiency in what factor would elevate PT without affecting PTT?

factor VII (only one that is unique to extrinsic)

30

what are the two paths to DHAP in the liver

glycolysis
glycerol kinase (only present in the liver, can get from Glycerol to G3P) --> DHAP by glycerol 3P Dehydrogenase
(the glycerol kinase mechanism is not present in adipocytes)