Pathology-Hemostasis

Question 1

What three main factors affect the formation of a thrombus?

Answer 1

Vascular wall, platelets, coagulation cascade

Question 2

Describe vasoconstriction during normal hemostasis

Answer 2

Neurologic reflect causes vasoconstriction and is amplified by endothelin

Question 3

What does endothelin do

Answer 3

increases vasoconstriction

Question 4

Describe what happens during primary hemostasis

Answer 4

1. wall expose so endothelium lays down vWF
2. GF1b on platelets binds vWF
3. Platelets release ADP and TXA2
4. Granules recruit more platelets

Question 5

What does vWF do

Answer 5

causes platelet adhesion

Question 6

What does GF1b do

Answer 6

binds vWF

Question 7

Dense granules

Answer 7

ADP, calcium, serotonin, histamine, epinephrine

Question 8

Alpha granules

Answer 8

V, VIII, protein s, fibrinogen

Question 9

What happens during secondary hemostasis?

Answer 9

1. Tissue factor is synthesized
2. Tissue factor and secreted platelet granules activate coagulation cascade
3. Activates thrombin that cleaves fibrinogen to fibrin to form secondary plug

Question 10

What does fibrinogen do?

Answer 10

Allows platelets to aggregate; forms dimers once cleaved

Question 11

5 steps of primary hemostasis

Answer 11

1. vasoconstriction
2. platelet adhesion
3. platelet activation and secretion
4. platelet aggregation
5. primary platelet plug

Question 12

What types of things activate the endothelium?

Answer 12

Infectious agents, hemodynamic factors, plasma mediators, most importantly cytokines

Question 13

How do PGI-2 and NO prevent thrombi formation

Answer 13

vasodilation

Question 14

Anticoagulant effects of endothelium

Answer 14

Heparin like molecules interact with antithrombin III, causing an inactivation of coat factors

Question 15

Antithrombin III

Answer 15

Inactivates thrombin so it cannot cleave fibrinogen

Question 16

Thrombomodulin

Answer 16

binds to thrombin and makes it activate C protein instead of cleaving fibrinogen

Question 17

Tissue-type plasminogen activator (TPA)

Answer 17

cleaves fibrin dimers so that it can clear a clot

Question 18

Plaminogen activator inhibitors (PAIs)

Answer 18

stop fibrinolysis

Question 19

How does vWF stay attached?

Answer 19

Via collagen

Question 20

Protein C and S

Answer 20

Vitamin K dependent proteins that activate V and VIII and cause anticoagulation

Question 21

Fibrinolysis

Answer 21

break down of fibrin into d-dimers

Question 22

Plasmin

Answer 22

derived from plasminogen; plays role in cleavage of fibrin

Question 23

Prostacylcin

Answer 23

made via arachidonic acid metabolism; causes vasodilation and inhibits coagulation