2.14 Pharm_ Intro to Blood clotting

Question 1

What are the 4 major events of hemostasis?

Answer 1

Hemostasis is composes of 4 major events that
occur in a set order:
Vasoconstriction
Platelet Actions: Adhesion, Activation,
Release or Secretion,
Aggregation
Fibrin Clot formation/coagulation
Fibrinolysis

Question 2

Thrombus vs embolus?

Answer 2

Thrombus: Blood clot
Embolus: fragment of traveling clot

Question 3

The major components of the hemostatic system are:

Answer 3

Vascular endothelium
Platelets
Coagulation system (Part 2: CPII)
Fibrinolytic system

Question 4

Most clotting factors and anticoagulants are made where? and what do they commonly require

Answer 4

Liver. Require Vit. K

Question 5

Name the following factors:

I
II
III

Answer 5

I: Fibrinogen
II: Prothrombin
III: Tissue factor

Question 6

What is the difference between FII and FIIa

Answer 6

Factor II = Prothrombin (a zymogen)
Factor IIa = Activated Factor II = Thrombin
(enzyme)

Question 7

What inhibits Aggretation by elevated levels of cGMP?

Answer 7

NO, Nitric oxide

Question 8

Prostacyclin inhibits what when what is elevated?

Answer 8

Prostacyclin inhibits aggregation and activation of platelets when cAMP is activated

Question 9

t-PA

Answer 9

Activates fibrinolysis. Activates Plasminogen to plasmin

Question 10

Primary homeostasis?

Answer 10

Platelet Plug formation

Question 11

What are the 3 mediators released by platelet activation that cause vasoconstriction?

Answer 11

serotonin (5-hydroxytryptamine; 5-HT) 
            thromboxane A2 (TXA2) - a prostaglandin
            epinephrine

Question 12

Response to injured vessel:

Exposure of blood to_______ that activates the intrinsic coagulation pathway.
Exposure of blood to ______FACTOR that activates the extrinsic coagulation pathway.

Answer 12

subendothelial COLLAGEN

subendothelial TISSUE

Question 13

Secondary homeostasis

Answer 13

Formation of fibrin clot

Question 14

Thrombin converts what to what?

Answer 14

Prothrombin is
converted to Thrombin;
Thrombin converts
Fibrinogen to Fibrin

Question 15

Platelets come from what type of cell?

Answer 15

Megakaryocytes

Question 16

Platelet function depends on what 3 things?

Answer 16

Platelet function depends on several integrin family glycoprotein receptors, a contractile cytoskeleton, and two types of cytoplasmic granules:

* α granules contain fibrinogen, clotting factors V and VIII
* dense bodies contain ADP, ionized calcium and serotonin

Question 17

Platelet adhsion:

How does a platelet bind to collagen?

Answer 17

Platelets bind indirectly to collagen via GPIb to von Willebrand factor (vWF) secreted by endothelial cells

Question 18

During platelet activation what is secreted?

Answer 18

TXA-2

Question 19

Go through the series of events during Platelet Adhesion, Activation, and Aggregation

Answer 19

Platelet Adhesion, Activation, and Aggregation
•Endothelial injury exposes the underlying basement membrane ECM; platelets adhere to the ECM (mainly collagen) primarily through binding of platelet GpIb receptors to vWF.
•Adhesion leads to platelet activation, an event associated with secretion of platelet granule contents, including calcium (a cofactor for several coagulation proteins) and ADP (a mediator of further platelet activation). Dramatic changes in shape and membrane composition occur along with activation of GpIIb/IIIa receptors. Activation also involves the production and secretion of TXA-2 which mediates further platelet activation and causes vasoconstriction.
•The GpIIb/IIIa receptors on activated platelets form bridging crosslinks with fibrinogen, leading to platelet aggregation.

Question 20

What inhibits fibrinolysis?

Answer 20

Alpha 2- antiplasmin

Plasminogen activator inhibitor (PAI)