Hemostasis and Thrombosis

Question 1

What is hemostasis?

Answer 1

process of blood clotting at the site of vascular injury

Question 2

What is a hemorrhagic disorder?

Answer 2

too little clotting

Question 3

What is a thrombotic disorder?

Answer 3

too much clotting

Question 4

What are the main cells involved in hemostasis?

Answer 4

platelets and endothelium

Question 5

What are the humoral factors involved in hemostasis?

Answer 5

plasma proteins and cellular contents

Question 6

What is the difference in function between primary and secondary hemostasis?

Answer 6

primary: makes platelet plug
secondary: platelet plug made stronger with fibrin mesh addition

Question 7

List the main steps in hemostasis.

Answer 7

vasoconstriction > primary hemostasis > secondary hemostasis > thrombus and antithrombotic events

Question 8

What factor binds platelets to the site of injury?

Answer 8

von Willebrand factor

Question 9

What protein allows platelets to interact with vW factor?

Answer 9

glycoprotein 1B (GpIb)

Question 10

What protein facilitates platelet aggregation?

Answer 10

glycoprotein 2b3a complex (GpIIb-IIIa)

Question 11

What are the main steps of primary hemostasis?

Answer 11

1. platelet adhesion (vW factor)
2. shape change
3. granule release (ADP, TxA2)
4. recruitment
5. aggregation (hemostatic plug)

Question 12

What are the two types of laboratory secondary hemostasis?

Answer 12

intrinsic

extrinsic

Question 13

What coagulation factors are associated with the intrinsic secondary pathway?

Answer 13

XII, XI, IX, VIII

Question 14

What coagulation factors are associated with the extrinsic secondary pathway?

Answer 14

VII, tissue factor

Question 15

What coagulation factors are common between the intrinsic and extrinsic pathways?

Answer 15

X, V, II (prothrombin), I (fibrinogen)

Question 16

Which ion immobilizes factors to the surface of the platelet plug?

Answer 16

Calcium

Question 17

What factors does thrombin upregulate?

Answer 17

XI, VIIIa, Va

Question 18

What coagulation factors are used in vivo during secondary hemostasis?

Answer 18

tissue factor, VII, IX, X, VIII, XI, X, V, II (prothrombin), I (fibrinogen)

Question 19

What stops the formation of the fibrin clot?

Answer 19

fibrinolytic system

Question 20

What enzyme cleaves fibrin into fibrin degradation products?

Answer 20

plasmin

Question 21

What circulating protein precipitates plasmin?

Answer 21

plasminogen (inactivated form)

Question 22

What prevents excessive fibrin degradation?

Answer 22

binding of free plasmin to alpha2 antiplasmin

Question 23

Which enzymes positively affect the fibrinolysis system?

Answer 23

tissue plasminogen activator (tPA) and urokinase

Question 24

Which enzymes negatively affect fibrinolysis?

Answer 24

plasminogen activator inhibitors (PAI)

Question 25

Which natural anticoagulant process inactivates thrombin?

Answer 25

antithrombin III + heparin like molecules

Question 26

How are factors Va and VIIIa inactivated?

Answer 26

with a combo of protein C and S

Question 27

What compounds released from endothelial cells inhibit platelet aggregation?

Answer 27

PGI2, NO, and adenosine diphosphatase

Question 28

What tests primary hemostasis?

Answer 28

Bleeding time/PFA-100

Question 29

What tests the intrinsic pathway?

Answer 29

PTT

Question 30

What tests the extrinsic pathway?

Answer 30

PT

Question 31

What tests fibrinolysis?

Answer 31

D-Dimer (show clotting degradation)