Blood Clotting

Front 1

GP1b alpha
(Glycoprotein 1b alpha)

Back 1

Platelet receptor for vWF.

Front 2

TXA2
(thromboxane A2)

Back 2

Released by activated platelets to activate others.
Binds the platelet TXA2 receptor.

Front 3

P2Y1 & P2Y12
(purinergic receptors)

Back 3

Platelet receptors for ADP.
Ligand binding activates platelet at site of injury.

Front 4

ADP

Back 4

Released by activated platelets to activate others.

Front 5

Par1 & Par4
(protease activated receptors)

Back 5

Platelet receptors for thrombin.
Ligand binding induces activation.

Front 6

alpha2A adrenergic receptor

Back 6

Platelet receptor for epinephrine.
Ligand binding induces activation.

Front 7

PGI2
(prostaglandin I2)

Back 7

Binds platelet receptor to inhibit activation.

Front 8

GPIIb-IIIa
(glycoprotein IIb- IIIa)

Back 8

Platelet receptor for fibrinogen.
Tethers 2nd layer of platelets.

Front 9

Glanzmann thrombasthenia

Back 9

Defect in platelet fibrinogen receptor GPIIb-IIIa.
Bleeding disorder.

Front 10

vonWillebrand disease

Back 10

Defective in vWF.
Bleeding disorder.

Front 11

Bernard-Soulier syndrome

Back 11

Defect in platelet receptor for vWF, GP1b alpha. Deffective platelet aggregation, giant platelets.
Bleeding disorder.

Front 12

Fibrinogen

Back 12

Cleaved by thrombin into fibrin and fibrinopeptides (from amino-terminal of alpha and beta chains).
6 peptide chains (2 alpha, 2 beta, 2 gamma).
Very prevalent in blood normally.

Front 13

Factor XIIIa
alpha2-AP

Back 13

Stabilizes fibrin network by forming covalent bonds (cross-linking).
Released from platelets in clot.
Activity is regulated by thrombin.

Front 14

Factor VII

Back 14

Extrinsic pathway.
Circulates in blood.
Contacts TF.
Activates factor X.

Front 15

TF

Back 15

Tissue factor, produced by non-endothelial cells in vascular wall when injury occurs.
Activates factors VII & X.
Membrane-bound protein.

Front 16

AT

Back 16

Antithrombin.
Serine protease inhibitor of thrombin and factor Xa.
Forms TAT complex with thrombin, with is 1000x more likely in presence of heparin.

Front 17

TFPI

Back 17

Tissue factor pathway inhibitor.
Inhibits the initiation complex of coagulation between TF and factors VIIa and Xa.

Front 18

Protein C
APC

Back 18

Anticoagulant pathway, activated protein C.
Circulates, is cleaved by thrombin bound to thrombomodulin.
With protein S, inactivates tenase and prothrombinase by cleaving VIIIa and Va.

Front 19

APC resistance

Back 19

Defect in coagulation factor V (fV Leiden mutation).
Thrombotic disorder, most common in caucasians.
Factor V is resistant to inactivation by APC.

Front 20

Plasmin

Back 20

Fibrinolysis.
Cleaves insoluble fibrin into soluble fibrin degradation products, fragments D-dimer and E, which are measured in patient's plasma.
Destroys factors V, VIII, and XII.

Front 21

uPA & tPA

Back 21

Urokinase-type plasminogen activator & tissue-type.
Converts plasminogen to plasmin.
Given in drug form.
tPA is released by damaged tissues once plasminogen gets trapped in clot.

Front 22

PAI-1

Back 22

Plasminogen activator inhibitor 1.

Front 23

Staphylokinase & streptokinase

Back 23

Bacterial activators of plasminogen.
Given in drug form.

Front 24

Recombinant factor VIII

Back 24

Most common drug therapy for bleeding disorders.

Front 25

Thrombocytopenia

Back 25

Bleeding disorder, mostly in small vessels, since platelets are the primary clotting factors there.
Platelet count below 50,000, and below 10,000 is lethal.
Treatment: whole blood or spleenectomy to cease platelet removal.

Front 26

Purified factor VII

Back 26

Given to trauma patients to limit blood loss & brain hemorrhage.

Front 27

Prothrombin

Back 27

Plasma protein, alpha2-globin.
Vit. K dependent synthesis.
Converted to thrombin by factor Xa.

Front 28

Factor Va

Back 28

Not proteolytic, but binds factor Xa and enhance's Xa's activity of thrombin formation.

Front 29

Prothrombinase

Back 29

Factor Xa + factor Va + platelets + calcium.
Amplified by thrombin.
Formation of prothrombinase is the rate-limiting step of clotting.

Front 30

Tenase

Back 30

Factor VIIIa + factor IXa + platelets + calcium.
Amplified by thrombin.

Front 31

Vitamin K dependant factors

Back 31

Coagulation: prothrombin, factors VII, IX, and X.
Anticoagulation: protein C and protein S.
Vitamin K is made by intestinal bacteria and used in liver.

Front 32

HMW Kininogen
(high molecular weight)

Back 32

Intrinsic pathway activator.
Produces factors XIIa and XIa.

Front 33

Thrombin

Back 33

Cleaves fibrinogen to fibrin and prothrombin to more thrombin.
Also activates factors VIII, IX, X, XI, and XII.
Activated from prothrombin by prothrombinase complex.

Front 34

Kallikrein

Back 34

Activates factor XII in intrinsic pathway.

Front 35

endogenous platelet activation inhibitors

Back 35

PGI2, Ecto-ADPase, NO.

Front 36

Thrombophilia

Back 36

Excessive clotting.
Factor V Leiden mutation or deficiency of protein C or S.

Front 37

Hemophilia A & B

Back 37

A: Factor VIII deficiency
B: Factor IX deficiency (Christmas disease).
X-linked recessive, common in men.

Front 38

Stasis

Back 38

Hypercoagulable state.
Huge clots form in legs when legs are propped up for long time periods. PE when pieces break off.
Treatment: tPA

Front 39

Disseminated intravascular coagulation

Back 39

Widespread clotting due to large amounts of dying tissue (releases TF) or sepsis.
Vessel blockage can lead to circulatory (septic) shock.

Front 40

Coumadin/Warfarin

Back 40

Anticoagulant.
Inhibits gamma-carboxylation of Vitamin K dependent factors. This decreases production by liver of clotting factors and prothrombin.

Front 41

Heparin

Back 41

Anticoagulant.
Enhances antithrombin activity.

Front 42

Hirudin/hirulog

Back 42

Anticoagulant.
Inhibits thrombin.

Front 43

GPIIb-IIIa blocking antibodies

Back 43

Antiplatelet.
Blocks fibrinogen receptors.

Front 44

COX inhibitors (NSAIDS, steroids) or phospholipase inhibitors

Back 44

Antiplatelet.
Inhibit TXA2 biosynthesis.

Front 45

Ticlopidine, Clopidogrel

Back 45

Antiplatelet.
Blocks ADP receptor.

Front 46

Factor X

Back 46

Common pathway.
As prothrombinase, activates prothrombin to thrombin.
Activated by factor VIIIa.

Front 47

Factor XII

Back 47

Intrinsic pathway.
Activated by kallikrein and HMW kininogen.
Converts factor XI to XIa.

Front 48

Factor XI

Back 48

Intrinsic pathway.
Activated by factor XIIa and HMW kininogen.
Converts factor IX to IXa.

Front 49

Factor IX

Back 49

Intrinsic pathway.
Activated by factor XIa.
Part of Tenase, converts factor X to Xa.

Front 50

Factor VIIIa

Back 50

Intrinsic pathway.
Part of tenase, converts factor X to Xa.

Front 51

Factor Va

Back 51

Common pathway.
Part of prothrombinase, converts prothrombin to thrombin.