Hemostasis

Question 1

What is hemostasis

Answer 1

the process of forming clots in the walls of damaged blood vessels and preventing blood loss

Question 2

What occurs initially in response to an injury during hemostasis

Answer 2

constriction of the vessel and formation of a temporary hemostatic plug of platelets

Question 3

loose aggregation of platelets in the temporary plug is bound together and converted into the definitive clot by

Answer 3

fibrin

Question 4

In fibrin, the formation of covalent cross-linkages to a dense, tight aggregate is catalyzed by which factor

Answer 4

factor XIII and requires Ca2+

Question 5

The conversion of fibrinogen to fibrin is catalyzed by

Answer 5

thrombin

Question 6

Prothrombin is converted to thrombin by

Answer 6

Factor X

Question 7

high-molecular-weight kininogen and kallikrein catalyzes which reaction

Answer 7

conversion of inactive factor XII to active factor XII (XIIa)

Question 8

What facilitates the binding of Antithrombin III to serine proteases in the coagulation system

Answer 8

Heparin

Question 9

All endothelial cells except those in the _________ microcirculation produce thrombomodulin

Answer 9

cerebral

Question 10

Is thrombin an anti or pro- coagulant

Answer 10

A procoagulant

Question 11

Thrombin becomes an anticoagulant when it binds to which molecule

Answer 11

thrombomodulin

Question 12

Function of plasmin

Answer 12

lyses fibrin and fibrinogen

Question 13

What is a natural anticoagulant

Answer 13

Heparin

Question 14

Which agents can bind to Ca2+ to prevent blood clotting

Answer 14

Chelating

Question 15

What are the anti-thrombotic properties of endothelial cells

Answer 15

Antiplatelet effects - prostacyclin (PGI2) and nitric oxide, adenosine diphosphatase that degrades ADP

Thrombomodulin

Protein C and protein S

Heparin like molecule

Fibrinolytic effects

Question 16

What are the pro-thrombotic properties of endothelial cells

Answer 16

Platelet effects: von Willebrand factor (vWF)

Procoagulant effects

Antifibrinolytic effects

Question 17

What is the hemostatic sequence in injured vessels?

Answer 17

Arteriolar vasoconstriction

Primary hemostasis (formation of platelet plug)

Secondary hemostasis

Clot stabilization and resolution

Question 18

What steps occur during primary hemostasis

Answer 18

von Willebrand factor (vWF) and collagen binds to subendothelial collagen

Activation of platelets + release of secretory granules

Platelet aggregation to form a primary hemostatic plug

Question 19

What steps occur during secondary hemostasis

Answer 19

Tissue factor binds and activates factor VII
Activation of coagulation cascade
formation of fibrin meshwork

Question 20

What is the function of the von Willebrand factor

Answer 20

acts as a bridge between the platelet surface glycoprotein(GpIb) and exposed collagen

Question 21

What is the role of platelets during hemostasis

Answer 21

formation of primary hemostatic plug

they change in shape which increases surface area

they secrete granules

Question 22

What are the two types of granules released by platelets during hemostasis

Answer 22

Alpha and dense granules

Question 23

Which molecule causes platelet aggregation and vasoconstriction

Answer 23

Thromboxane A2

Question 24

Which molecule causes platelet aggregation and change in GpIIb-IIIa configuration for fibrinogen bridging

Answer 24

ADP

Question 25

what is Glanzmann thrombosthenia

Answer 25

the deficiency of GpIIb-IIIa, involved in platelet aggregation

Question 26

What is Bernard-Soulier syndrome

Answer 26

the defect in GpIb (binds to Willebrand factor)

Question 27

What molecule activates the coagulation cascade (extrinsically)

Answer 27

factor VII

Question 28

What is the ultimate purpose of the coagulation cascade

Answer 28

To turn fibrinogen into its active for fibrin so clot stabilization can occur.

Question 29

What is the other name for tissue factor II

Answer 29

Prothrombin

Question 30

what is the other name for tissue factor IIa

Answer 30

thrombin

Question 31

What are the proteins in the extrinsic pathway

Answer 31

factors VII, X, II, V, and fibrinogen

Question 32

what does a PT assay do

Answer 32

assesses the function of the proteins in the extrinsic pathway

Question 33

Which measurements are used to assess the anticoagulant effect of warfarin

Answer 33

PT and INR(International normalized ratio)

Question 34

what does a PTT assay do

Answer 34

Screens for the function of the proteins in the intrinsic pathway

Question 35

What are the proteins in the intrinsic pathway

Answer 35

factors XII, XI, IX, VIII, X, V, II, and fibrinogen

Question 36

Define thrombin time

Answer 36

Ability to convert fibrinogen to fibrin clot( Measure of circulating fibrinogen)

Question 37

Which molecule breaks down fibrin

Answer 37

plastin

Question 38

What is the fibrinolytic cascade

Answer 38

it moderates the size of the clot

Question 39

Examples of tissue plasminogen activator

Answer 39

Urokinase-like PA (u-PA) Streptokinase

Question 40

Examples of Sudden massive bleeding disorders

Answer 40

Aortic dissection in Marfan’s syndrome Ventricular rupture following MI

Question 41

Examples of Mild bleeding disorders

Answer 41

von Willebrands disease Coagulation factor deficiencies

Question 42

Examples of Generalized defects involve blood vessels

Answer 42

Ecchymosis Palpable purpura Hematoma Vasculitidis

Question 43

Examples of Defects of secondary hemostasis

Answer 43

Coagulation factor deficiencies Bleeding into soft tissues and joints Hemarthrosis Intracranial hemorrhage

Question 44

Defects of primary hemostasis

Answer 44

``` Platelet or VWD Small bleeds in skin and mucous membranes Petechiae ( 1-3mm) Purpura ( 3mm) Bleeding in mucous membranes Menorrhagia Epistaxis Intracranial and gastrointestinal bleeding ```

Question 45

What is Disseminated intravascular coagulation (DIC)

Answer 45

Complications of large number of conditions associated with systemic activation of thrombin OR Sudden or insidious onset of widespread fibrin thrombi in the microcirculation

Question 46

What causes Disseminated intravascular coagulation (DIC)

Answer 46

Obstetric complications Advanced malignancy

Question 47

What is the pathogenesis of Disseminated intravascular coagulation (DIC)

Answer 47

Release of tissue factor and widespread endothelial injury