Intrinsic and Extrinsic Coagulation Pathways (Choudhury)

Question 1

plasminogen

Answer 1

produced by liver. t-PA activates plasminogen to plasmin

Question 2

Plasmin

Answer 2

degrades fibrin indo fibrin degradation product (FDP)

Question 3

major players in extrinsic pathway for coagulation

Answer 3

tissue factor thromboplastin will activate factor VII so it can trigger activation of factor X in the common pathway

Question 4

Major players in the intrinsic pathway for coagulation

Answer 4

factor XII(hageman) which activates XI to activate IX.
IX works with VIIIa to activate X in common pathway

Question 5

Describe common pathway of coagulation

Answer 5

When X is activated it will activate conversion of prothrombin to thrombin with the help of factor Vactivated and Ca2+
Thrombin then activates XIII and converts fibrinogen into fibrin

Question 6

What causes propagation of coagulation pathways

Answer 6

Initiation that generates IIa will activate propagation

Question 7

Anti-thrombin III

Answer 7

inactivates IIA, IXa and Xa

Question 8

what does activated protein C do in coagulation

Answer 8

deactivates Va and VIIIa. Occurs when thrombin (IIa) combines with thrombomodulin

Question 9

most important coagulation factor

Answer 9

thrombin

Question 10

Prothrombin

Answer 10

prothrombin activator and Ca2+ convert prothrombin into thrombin

Question 11

What type of feedback does thrombin give?

Answer 11

positive feedback to produce more

Question 12

What does thrombin activate

Answer 12

converts fibrinogen to fibrin and activates fibrin-stabilizing factor XIII which in presence of Ca2+ stabilizes fibrin polymer through covalent bonding of fibrin monomers

Question 13

what activates t-PA activity

Answer 13

fibrin (neg feedback)

Question 14

What are the anti-coagulant properties?

Answer 14

heparin sulphate, thrombomodulin, Protein S and tissue factor Pathway inhibitor (TFP1)

Question 15

Heparin Sulphate

Answer 15

activates Antithrombin III

Question 16

Thrombomodulin

Answer 16

binds to thrombin and converts it from a procoagulatnt to anti by activating Protein C

Question 17

TFPInhibitor

Answer 17

inhibits tissue factors VIIa and Xa

Question 18

Normal sequence of events for hemostasis

Answer 18

Primary, secondary, anti thrombosis and fibrinolysis

Question 19

Endothelin

Answer 19

acts on sm mm to cause vasoconstriction

Question 20

what is contained in the dense granules

Answer 20

serotonin, ADP-platelet activator and aggregator, calcium

Question 21

what is contained in the a granules

Answer 21

Coagulation factors, fibrinogen and PDGF

Question 22

how long does it take for the primary plug to form

Answer 22

3-5 min

Question 23

“fibrin polymerization”

Answer 23

secondary hemostasis when the cementing of platelets take place to form hemostatic plug.
5-10 min

Question 24

How is the common pathway triggered

Answer 24

VIIa triggers common pathway via factor X in extrinsic

Intrinsically- VIIIa works with Ca to activate X

Question 25

thromboplastin

Answer 25

factor III, a membrane-bound lipoprotein that is released by injured endothelial cells

Question 26

General scheme and name of factors in extrinsic pathway

Answer 26

Thromboplasin III interacts with proconvertinVII and Ca2+ to activate the Stuart factor X

Question 27

main role of factor X the stuart factor

Answer 27

to activate prothrombin activator.

Question 28

General scheme and names of factors in intrinsic pathway

Answer 28

Exposed collagen activates Hageman factor XII which activates plasma thromboplastin anteceded PTA XI which with Ca2+ activate christmas factor IX which interacts with anti-hemophilic factor VIII. VIII plus Ca2+ activates stuart factorX

Question 29

General scheme of common pathway with name of factor

Answer 29

Activated X interacts with Ca2+ and accelerin V to form prothrombin activator

Question 30

What converts prothrombin into thrombin

Answer 30

prothrombinase (protrhombin activator) in presence of Ca2+

Question 31

Urokinase-plasminogen activator

Answer 31

u-PA secreted by kidney circulates as inactie single-chain form (scu-PA) which must be converted by plasmin to for tcu-PA