Hemodynamic Disorders (4) - Hemostasis, section 2

Question 1

Hemostasis

Answer 1

Formation of a blood clot to stop blood flow

Question 2

What are the 4 steps to Hemostasis

Answer 2

1. Arterial Vasoconstriction
2. Primary Hemostasis - platelet plug
3. Secondary Hemostasis - fibrin deposition
4. Clot stabilization and resorption

Question 3

What causes vasoconstriction?

Answer 3

Endothelin

Question 4

What are the 3 steps of platelets during primary hemostasis?

Answer 4

1. Adhesion
2. Activation
3. Aggregation

Question 5

What molecule on the subendeothelial surface is involved with platelet adhesion?

Answer 5

Von Willebrand Factor (vWF)

Question 6

What molecule on the platelet surface is involved with platelet adhesion?

Answer 6

GP1b

Question 7

What binds to what for platelet adhesion during primary hemostasis?

Answer 7

GP1b binds to Von Willebrand Factor

Question 8

What molecule activates platelets during primary hemostasis?

Answer 8

Thrombin

Question 9

Platelet activation involves 3 structural changes. Describe those.

Answer 9

1. Conformational change of the platelet (increased surface area) and GP2b-3a (concave)
2. Negatively charged platelet surface

Question 10

Platelet activation involves release of 2 types of granules. What are those?

Answer 10

Dense granules

Alpha granules

Question 11

Platelet activation causes release of granules from the platelet. What molecule release causes more platelet activation?

Answer 11

ADP

Question 12

Platelet activation causes release of granules from the platelet. What molecule release causes platelet aggregation?

Answer 12

Thromboxane A2

Question 13

What does Aspirin inhibit?

Answer 13

Thromboxane A2 - Platelet aggregation during primary hemostasis

Question 14

For platelet aggregation, what receptor on the platelet is involved?

Answer 14

GP2b-3a

Question 15

For platelet aggregation, what binds to GP2b-3a?

Answer 15

Fibrinogen

Question 16

Fibrinogen binding to GP2b-3a allows for?

Answer 16

Cross linking of platelets and forms platelet plug

Question 17

What is contained in endothelial cells and is a source of von willebrand factor?

Answer 17

Weibel Palade Bodies

Question 18

Where does von willebrand factor come from?

Answer 18

Weibel Palade Bodies in the endothelial cells

Question 19

Von willebrand factor disease

Answer 19

Lack of von willebrand factor

- Trouble with platelet adhesion

Question 20

Bernard Soulier Syndrome

Answer 20

Lack of GP1b

- Trouble with platelet adhesion

Question 21

How do platelets appear with Bernard Soulier Syndrome?

Answer 21

GIANT

Question 22

Glanzmann Thrombasthenia

Answer 22

Lack of GP2b-3a

- Trouble with platelet aggregation

Question 23

Thrombocytopenia

Answer 23

LOW platelets (less than 50K)

Question 24

What occurs during secondary hemostasis?

Answer 24

Fibrin deposition and coagulation cascade

= clot stabilization

Question 25

Describe the Intrinsic pathway of secondary hemostasis

Answer 25

Factor XII Factor XI Factor IX + Factor VIII - Common pathway

Question 26

Describe the Extrinsic pathway of secondary hemostasis

Answer 26

Tissue factor + Factor VII | - Common pathway

Question 27

Describe the Common pathway of secondary hemostasis

Answer 27

``` Factors IX, VIII, VII activate Factors X and V Factor II (thrombin) Fibrinogen activated to Fibrin = stable clot ```

Question 28

What measures the Extrinsic pathway

Answer 28

PT (prothrombin time)

Question 29

What measures the Intrinsic pathway

Answer 29

aPTT

Question 30

PT test

Answer 30

Tissue factor + blood | - A clot should form in less than 14 seconds

Question 31

aPTT test

Answer 31

Negative surface calcium + blood | - A clot should form in less than 45 seconds

Question 32

Anti - Hemophilic A factor

Answer 32

Factor VIII

Question 33

Vitamin K dependent factors require?

Answer 33

Calcium

Question 34

What are the Vitamin K dependent factors?

Answer 34

2, 7, 9, 10

Question 35

Main activities of thrombin?

Answer 35

Activate platelets | Stabilize fibrin

Question 36

Coumadin (warfarin) inhibits?

Answer 36

Vitamin K - cannot activate factors 2, 7, 9, 10

Question 37

The _____ can regulate clot formation and dissolution

Answer 37

Endothelium

Question 38

What 3 things can the Endothelium produce to INHIBIT platelets?

Answer 38

1. Adenosine DisphophatASE - blocks ADP which activates platelets 2. NO 3. Prostacyclins

Question 39

What can the Endothelium produce to break down fibrin?

Answer 39

Tissue Plasminogen Activator (t-PA)

Question 40

How does Tissue Plasminogen Activator (t-PA) break down fibrin?

Answer 40

It activates Plasmin! | Plasmin then breaks apart Fibrin and degrades the clot

Question 41

Cascade of events of the fibrinolytic activity of the Endothelium

Answer 41

- Endothelium produces t-PA - t-PA activates Plasmin - Plasmin breaks Fibrin apart and degrades clot

Question 42

What inhibits plasmin?

Answer 42

Alpha2 - antiplasmin -- keeps clot stable

Question 43

What receptors on the endothelium can bind Thrombin and exert anti-coagulation effects?

Answer 43

Thrombomodulin

Question 44

Once Thrombomodulin binds Thrombin, then what happens?

Answer 44

Activates protein C and S which INHIBIT factors 5 and 8 | = Anticoagulation

Question 45

Heparin-like molecules on the endothelial surface activate _____ which inhibits ______

Answer 45

Antithrombin III | Thombin

Question 46

Small bleeds (petechiae and purpura) are due to defects in?

Answer 46

Primary hemostasis

Question 47

How do defects in primary hemostasis present?

Answer 47

Nosebleeds Excessive menstruation GI bleeds

Question 48

Bleeds in joints (hemarthrosis) are due to defects in?

Answer 48

Secondary hemostasis

Question 49

Secondary hemostasis defects cause?

Answer 49

Bleeds in joints (hemarthrosis)

Question 50

Generalized defects of small vessels cause?

Answer 50

Eccyhmoses