Hemostasis and Blood Coagulation

Question 1

Hemostasis refers to the process by which _____

Answer 1

active bleeding is stopped.

Question 2

Hemostasis occurs in four general steps:

Answer 2

○ Constriction/spasm of the damaged blood vessel
○ Formation of a Platelet Plug
○ Blood clot formation via coagulation
○ Reinforcement of clot with Fibrin

Question 3

Primary hemostasis occurs at the level of the _____

Answer 3

Platelets

Question 4

Seconday hemostasis occurs at the level of the ______

Answer 4

Coagulation factors

Question 5

Platelet lifespan

Answer 5

7-10 days

Question 6

Platelets contain mitochondria, smooth endoplasmic reticulum, and many _____

Answer 6

granules filled with clotting factors and cytokines.

Question 7

Platelet Granules secrete various substances:

Answer 7

○ Adenosine Diphosphate (ADP)-
○ von Willebrand Factor (vWF)-
○ Fibrinogen-

Question 8

Adenosine Diphosphate (ADP)- binds to receptors on other platelets, _____

Answer 8

activating/recruiting.

Question 9

von Willebrand Factor (vWF)- Also secreted by damaged endothelium, binds ____

Answer 9

exposed collagen to platelet surface glycoproteins.

Question 10

Fibrinogen- Already present in
plasma as well, precursor to ____

Answer 10

Fibrin.

Question 11

Granule glycoproteins

Answer 11

Glycoprotein Ib-
Glycoprotein IIb/IIIa-

Question 12

These glycoproteins bind to plasma Thrombospondin and Fibrinogen, which contribute to Platelet Aggregation

Answer 12

Glycoprotein IIb/IIIa-

Question 13

A cell surface protein that vWF is able to bind, adhering the platelet to the endothelium.

Answer 13

Glycoprotein Ib-

Question 14

Formation of the platelet plug involves several steps:

Answer 14

1) Endothelial injury
2) Exposure and Adhesion
3) Activation (of platelets)
4) Aggregation (of platelets)

Question 15

Describe process of platelet plug

Answer 15

See slide 16-19

Question 16

The platelet plug is fairly _____

Answer 16

unstable

Question 17

Last step in primary hemostasis

Answer 17

Thrombospondin and Fibrinogen cross-link
together, clumping one platelet to a nearby platelet. (E)

Question 18

Coagulation via the Coagulation Cascade/Network converts the Platelet Plug into _____

Answer 18

a more stable clot.

Question 19

Extrinsic Pathway is Activated by the presence of a protein called _____.

Answer 19

Tissue Factor

Question 20

Tissue Factor binds to _____, activating it
(VIIa); This complex then catalyzes the activation of Factor X.

Answer 20

Factor VII

Question 21

Intrinsic Pathway is Activated by exposure to _____ located around damaged endothelium.

Answer 21

collagen fibers

Question 22

there is some cross activation of ____ as well from both pathways.

Answer 22

Factor IX

Question 23

Ultimately, the end result or goal of both the Intrinsic and Extrinsic Pathways is to activate ______.

Answer 23

Factor X (Xa)

Question 24

In the Common Pathway, The activated Factors IX (IXa) and VII (VIIa) help to facilitate
the activation of _____

Answer 24

Factor X.

Question 25

Activated Factor X helps to convert ____ to _____.

Answer 25

Prothrombin; Thrombin

Question 26

Thrombin facilitates the conversion of the inactive ____ to ____.

Answer 26

Fibrinogen; Fibrin

Question 27

Once activated, ____ monomers are then stabilized in polymers by ____ and cross-linked together.

Answer 27

Fibrin; Factor XIII

Question 28

Nearly all clotting factors are formed in the liver. ____is essential to help these factors to mature.

Answer 28

Vit K

Question 29

Vit K is continually _____ in the intestinal tract by bacteria.

Answer 29

synthesized

Question 30

Vit K is a key component for the formation of:

Answer 30

○ Factor II ○ Factor VII ○ Factor IX ○ Factor X ○ Protein S ○ Protein C

Question 31

T/F TOO MUCH of either bleeding or clotting can be deadly

Answer 31

T

Question 32

Factors that inhibit Primary Hemostasis (Platelet Aggregation)

Answer 32

○ Smoothness of the undamaged endothelial lining. ○ Mucosal layer of the endothelium (Glycocalyx) repels clotting factors. ○ Prostacyclin and Nitric Oxide released from uninjured endothelium that vasodilate healthy endothelium and prevent excessive platelet aggregation. ■ Keep platelet plug localized to injury

Question 33

Factors that inhibit Secondary Hemostasis (Coagulation Cascade)

Answer 33

○ Protein C ○ Protein S ○ Antithrombin III

Question 34

Protein ___ is activated by Thrombin.

Answer 34

C

Question 35

Activated Protein C, with the help of Protein S, inactivates _____.

Answer 35

Factor VIII and Factor V

Question 36

_____ is a protein circulating in the plasma and in vascular endothelium, and serves as a coagulation regulator.

Answer 36

Antithrombin III

Question 37

Enzymatic breakdown of fibrin in blood clots is called

Answer 37

Fibrinolysis

Question 38

Factors involved in Fibrinolysis

Answer 38

○ Plasminogen: Inactive protein in the plasma. ○ Tissue Plasminogen Activator (tPA): Present in endothelial cells and minimally in the plasma. Activates Plasminogen into Plasmin ○ Plasmin: Over time, Plasmin in a clot will degragrades fibrin.

Question 39

Disorders of Primary Hemostasis (Platelets) involve

Answer 39

Low platelet count or some form of platelet dysfunction. Examples: ○ Thrombocytopenia ○ von Willebrand’s Disease ○ Immune (Idiopathic) Thrombocytopenic Purpura (ITP) ○ Thrombotic Thrombocytopenic Purpura (TTP) ○ Hemolytic Uremic Syndrome (HUS)

Question 40

Disorders of Secondary Hemostasis (Clotting Factors) involve

Answer 40

Factor deficiencies or dysfunctions within the Coagulation Cascade. Examples: ○ Hemophilia A (VIII) ○ Hemophilia B (IX) ○ Liver Disease-Induced ○ Vitamin K Deficiency

Question 41

In order to evaluate for these disorders of hemostasis, we generally order a ____

Answer 41

Coagulation Panel

Question 42

Coagulation panel items

Answer 42

○ CBC (for the Platelet Count) ■ Additional platelet function tests are available if required ○ Prothrombin Time (PT/INR) ■ Primary evaluates Extrinsic and Common Pathways ○ Partial Thromboplastin Time (PTT) ■ Intrinsic and Common Pathways

Question 43

Hemophilia A is hereditary bleeding disorder that is considered _____

Answer 43

X-Linked Recessive.

Question 44

Pathophysiology of Hemophilia A

Answer 44

○ Deficiency in Coagulation Factor VIII. ○ Factor IX is unable to activate Factor X, so coagulation is dysfunctional.

Question 45

Characteristic Signs and Symptoms of hemophilia A

Answer 45

○ Experiencing hemorrhages in deep tissue is characteristic. ○ Spontaneous Hemarthrosis – essentially diagnostic! ■ Most common joints are knees, ankles, and elbows ○ Big spontaneous bleeds occur only in severe disease. ○ Mild disease requires a little trauma.

Question 46

definitive diagnosis for hemophilia A

Answer 46

Coagulation Factor VIII Assay will show decreased levels.

Question 47

Treatment for Hemophilia A

Answer 47

○ Repeated hemarthrosis may lead to joint deformities. ○ Avoid any contact sports, Aspirin, and IM injections. ○ IV infusion of Factor VIII concentrate during acute bleed. ■ Severe cases get 2-3 x / wk prophylactically