Deck 24: Introduction to Hemostasis

Question 1

Platelet membrane glycoprotein Ib is the receptor for __________, which serves to mediate the adhesion of platelets to subendothelium.

A) von Willebrand factor
B) Christmas factor
C) Tissue factor
D) Stuart-Prower factor
E) Hageman factor

Answer 1

von Willebrand factor

Question 2

Platelets are cellular fragments derived from the cytoplasm of __________ present in the bone marrow.

A) Granulocytes
B) Megakaryocytes
C) Lymphocytes
D) Plasma cells
E) None of the above

Answer 2

Megakaryocytes

Question 3

Glycocalyx, a mucopolysaccharide, coats the luminal surface of the endothelium and possesses the ability to stimulate weakly the physiologic anticoagulant __________.

A) Coumarin
B) Heparin
C) Antithrombin III
D) Warfarin
E) None of the above

Answer 3

Antithrombin III

Question 4

Which constituent of the peripheral zone contain glycoproteins responsible for blood group specificity (ABO), tissue compatibility [human leukocyte antigen (HLA)], and platelet antigenicity?

A) Glycocalyx
B) Plasma membrane
C) Open canalicular system
D) Submembranous region
E) None of the above

Question 5

What is the function of tissue thromboplastin in maintaining vascular integrity?

A) Initiates fibrin formation through the extrinsic pathway of the coagulation system
B) Initiates fibrin formation through the intrinsic pathway of the coagulation system
C) Initiates fibrin lysis through the extrinsic pathway of the coagulation system
D) Initiates fibrin lysis through the intrinsic pathway of the coagulation system
E) None of the above

Question 6

The vascular system acts to prevent bleeding by which mechanism(s)?

A) Vasoconstriction and reflex stimulation of adjacent vessels
B) Diversion of blood flow around damaged vasculature
C) Initiation of contact-activation of platelets with subsequent aggregation
D) Contact-activation of the coagulation system leading to fibrin formation
E) All of the above

Question 7

The peripheral zone is a complex region of the platelet consisting of:

A) Glycocalyx
B) Plasma membrane
C) Open canalicular system (OCS)
D) Submembranous region
E) All of the above

Question 8

The average diameter of the platelet is __________.

A) 2-4 µm
B) 6-8 µm
C) 10-12 µm
D) 18-20 µm
E) None of the above

Question 9

What is the function of tissue plasminogen activator (TPA)?

A) Inhibits platelet response
B) Activates plasmin to plasminogen and lyses the fibrin clot
C) Activates plasminogen to plasmin and lyses the fibrin clot
D) Stimulates antithrombin III
E) None of the above

Question 10

All of the following are major systems involved in maintaining hemostasis except:

A) Vascular system
B) Kinin system
C) Platelets
D) Fibrin-forming (coagulation) system
E) Fibrin-lysing (fibrinolytic) system

Question 11

Bleeding from arterioles and venules results in pinpoint __________ hemorrhage.

A) Petechial
B) Ecchymoses
C) Epistaxis
D) All of the above
E) None of the above

Question 12

The platelet membrane represents a fluid lipid bilayer composed of:

A) Glycoproteins
B) Glycolipids
C) Lipoproteins
D) All of the above
E) None of the above

Question 13

__________ functions as a potent vasodilator and inhibitor of the platelet response.

A) Prostacyclin (PGI₂)
B) Protein C
C) ADPase
D) Vitamin D
E) None of the above

Question 14

The platelet structure is composed of:

A) Peripheral zone
B) Sol-gel zone
C) Organelle zone
D) All of the above
E) None of the above

Question 15

Which of the following include specificities of plasma membrane receptors within the peripheral zone?

A) ADP
B) Thrombin
C) Glycoprotein IIa
D) Serotonin
E) All of the above

Question 16

What is the normal platelet count?

A) 300,000 to 500,000/µL
B) 150,000 to 400,000/µL
C) 500,000 to 700,000/µL
D) 50,000 to 150,000/µL
E) None of the above

Question 17

Primary hemostasis is defined as:

A) The process of removing unwanted fibrin deposits following vascular injury
B) The process of cleaving fibrin degradation products into D and E fragments
C) The process of cleaving fibrin degradation products into D and Y fragments
D) The interaction of platelets and the vascular endothelium in halting bleeding following vascular injury
E) None of the above

Question 18

Hemorrhaging from veins results in large, ill-defined, soft tissue bleeding termed __________.

A) Petechiae
B) Ecchymoses
C) Epistaxis
D) All of the above
E) None of the above

Question 19

In the peripheral blood, approximately __________ percent of the platelets are sequestered in the spleen as functional reserves.

A) 10%
B) 20%
C) 30%
D) 40%
E) None of the above

Question 20

The clear zone of cytoplasm that surrounds a higher stained granulomere is termed __________.

A) Collagen
B) Glycocalyx
C) Hyalomere
D) Centromere
E) None of the above

Question 21

What is necessary for platelet aggregation?

A) ADP
B) Fibrinogen
C) Calcium
D) All of the above
E) None of the above

Question 22

Platelet factor III facilitates __________ formation by the intrinsic coagulation system.

A) Plasmin
B) Thrombin
C) Fibrinogen
D) Fibrin
E) None of the above

Question 23

All of the following are effective in aggregating platelets in vitro except:

A) ADP
B) Magnesium
C) Collagen
D) Epinephrine
E) Thrombin

Question 24

__________ is a reversible process whereby platelets stick to a foreign surface.

A) Aggregation
B) Adhesion
C) Reverse reaction
D) Agglutination
E) Secretion

Question 25

Platelet aggregation results in __________ as measured by a platelet aggregometer.

A) Increased absorbance
B) Decreased transmittance
C) Decreased absorbance
D) Increased light scatter
E) None of the above

Question 26

Platelets will not aggregate in the absence of membrane __________.

A) Glycoprotein
B) Fibrinogen-binding sites
C) Fibrinogen
D) Calcium
E) All of the above are necessary for platelet aggregation

Question 27

Platelet factor 4 (PF4) neutralizes which anticoagulant?

A) Protein C
B) Heparin
C) Warfarin
D) Coumarin
E) None of the above

Question 28

Adhesion of platelets to subendothelial fibers is dependent on a plasma protein called __________.

A) Hageman factor
B) Stuart-Prower factor
C) Christmas factor
D) von Willebrand factor
E) tissue factor

Question 29

The organelle region is responsible for the __________ activities of the platelet.

A) Metabolic
B) Physical
C) Kinetic
D) Enzymatic
E) None of the above

Question 30

Platelet stored products are released through the __________.

A) Glycocalyx
B) Plasma membrane
C) OCS
D) Mitochondria
E) None of the above

Question 31

Activation of platelets results in which of the following?

A) Stickiness
B) Adhesion
C) Shape change
D) Aggregation
E) All of the above

Question 32

All of the following are true regarding the secondary wave of aggregation except:

A) It is dependent on the activation stimulus to evoke secretion of platelet granules.
B) It is an energy-dependent process.
C) It is a reversible process.
D) It is dependent on ADP, serotonin, and epinephrine.
E) None of the above is true.

Question 33

The organelle zone is composed of __________.

A) Alpha granules
B) Dense granules
C) Lysosomes
D) Glycogen
E) All of the above

Question 34

The term used to describe the sol-gel zone is:

A) Plasma membrane
B) Cytoskeleton
C) Peroxisomes
D) Glycocalyx
E) None of the above

Question 35

The function of platelets in hemostasis includes which of the following?

A) Maintenance of vascular integrity
B) Initial arrest of bleeding by platelet plug formation
C) Stabilization of the hemostatic plug by contributing to the process of fibrin formation
D) All of the above
E) None of the above

Question 36

Which substance induces dense and alpha granule secretion?

A) Thromboxane A₂ (TXA₂)
B) ADP
C) Epinephrine
D) Thrombin
E) All of the above

Question 37

What major contractile protein in the platelet cytosol accounts for 20-30% of total platelet protein and functions within microtubules in organizing parallel filaments capable of contraction?

A) Sphingomyelin
B) Myelin
C) Myosin
D) Actin
E) None of the above

Question 38

In the process of aggregation, fibrinogen binds to the calcium complex of platelet membrane __________.

A) Glycoproteins Ib-IIIa
B) Glycoproteins IIb-IIIa
C) Glycoproteins Ib-IIa
D) Glycoproteins Ia-IIIa
E) None of the above

Question 39

Platelets do not aggregate in Glanzmann's thrombasthenia when:

A) Platelets lack Ib and IIIb
B) Calcium deficiency
C) Platelets express GPIIb and GPIIIa
D) Platelets lack GPIIb and GPIIIa
E) None of the above

Question 40

Thromboxane A₂, a potent aggregating agent of platelets, mediates the platelet __________ in addition to vasoconstriction.

A) Adhesion
B) Precipitation
C) Release reaction
D) All of the above
E) None of the above

Question 41

What role do membrane phospholipids play in the coagulation process?

A) They are inhibitors of cyclo-oxygenase.
B) They are responsible for the synthesis of TXA₂.
C) They provide a catalytic surface for the activation of various clotting factors.
D) They convert fibrinogen to fibrin.
E) None of the above

Question 42

What is the coagulation factor assigned as factor V?

A) Calcium
B) Fibrinogen
C) Stabile factor
D) Labile factor
E) None of the above

Question 43

What is meant by the term viscous metamorphosis?

A) An irreversible aggregation of a mass of degenerative platelet material without membrane
B) A reversible aggregation of a mass of degenerative platelet material without membrane
C) Inhibition of the initial aggregation of platelets
D) Inhibition of an irreversible aggregation of mass of degenerative material with membrane
E) None of the above

Question 44

What is the correct sequence of events in hemostatic plug formation?

A) Aggregation, adhesion, plug formation, consolidation, fibrin stabilization
B) Consolidation, aggregation, adhesion, fibrin stabilization, plug formation
C) Adhesion, aggregation, consolidation, plug formation, fibrin stabilization
D) Adhesion, aggregation, plug formation, consolidation, fibrin stabilization
E) None of the above

Question 45

What is the end product of coagulation?

A) Thrombin
B) Fibrinogen
C) Prothrombin
D) Fibrin
E) None of the above

Question 46

What is the coagulation factor assigned as factor II?

A) Fibrinogen
B) Prothrombin
C) Stuart-Prower factor
D) Hageman factor
E) None of the above

Question 47

Factor XIII is assigned as what coagulation protein?

A) Antihemophilic factor
B) Fibrin-stabilizing factor
C) Christmas factor
D) Hageman factor
E) None of the above

Question 48

With the exception of factor VIII, all the coagulation factors are produced in the __________.

A) Bone marrow
B) Liver
C) Kidney
D) Spleen
E) None of the above

Question 49

Factor X is assigned as what coagulation protein?

A) Antihemophilic factor
B) Christmas factor
C) Stuart-Prower factor
D) Hageman factor
E) None of the above

Question 50

What is the coagulation protein assigned as factor I?

A) Calcium
B) Prothrombin
C) Fibrinogen
D) Labile factor (proaccelerin)
E) None of the above

Question 51

Which of the following represents factor IV?

A) Prothrombin
B) Stuart-Prower factor
C) Calcium
D) Hageman factor
E) None of the above

Question 52

What is the coagulation factor assigned as factor VII?

A) Stabile factor
B) Prothrombin
C) Labile factor
D) Fibrinogen
E) None of the above

Question 53

What prostaglandin produced in the endothelium is a vasodilator and potent inhibitor of platelet aggregation?

A) TXA₂
B) PGG₂
C) PGI₂
D) PGH₂
E) None of the above

Question 54

Aspirin prevents aggregation of platelets due to:

A) Inactivation of PGI₂
B) Inactivation of platelet cyclo-oxygenase
C) Amplification of PGI₂
D) Inability of megakaryocytes to synthesize cyclo-oxygenase
E) None of the above

Question 55

The release reaction from dense granules involves the secretion of __________.

A) ADP
B) Serotonin
C) Calcium
D) All of the above
E) None of the above

Question 56

What is the coagulation factor assigned as factor VI?

A) Calcium
B) Fibrinogen
C) Hageman factor
D) Christmas factor
E) None of the above

Question 57

Antihemophilic factor corresponds to __________.

A) Factor II
B) Factor IX
C) Factor VIII
D) Factor XII
E) None of the above

Question 58

The last stage involved in arresting bleeding after vessel damage is the formation of a __________.

A) Fibrin degradation product
B) Stable platelet plug
C) Plasmin synthesizer
D) Vasodilator
E) None of the above

Question 59

What is the coagulation factor assigned as factor III?

A) Tissue thromboplastin
B) Fibrinogen
C) Calcium
D) Christmas factor
E) None of the above

Question 60

Thrombin on the aggregated platelets surface converts __________ to fibrin.

A) Fibrinogen
B) Plasmin
C) Prothrombin
D) Platelet factor III
E) None of the above

Question 61

The extrinsic system of coagulation is monitored by the __________.

A) Activated partial thromboplastin time (APTT)
B) Prothrombin time (PT)
C) Fibrinogen assay
D) Thrombin time (TT)
E) Reptilase time

Question 62

The intrinsic system of coagulation is measured by the __________.

A) APTT
B) PT
C) Fibrinogen assay
D) TT
E) Reptilase time

Question 63

All of the following are characteristics of the prothrombin group of coagulation proteins except:

A) Factors are absorbed by BaSO₄.
B) Vitamin K dependent.
C) Coagulation proteins are decreased in patients who are vitamin K deficient.
D) All factors are consumed during coagulation.
E) None of the above.

Question 64

The prothrombin proteins are comprised of:

A) Factors II, VIII, IX, X
B) Factors II, VII, IX, X
C) Factors I, VII, IX, X
D) Factors II, V, VII, X
E) None of the above

Question 65

What is the substrate of the coagulation system?

A) Prothrombin
B) Fibrinogen
C) Antihemophilic factor
D) Calcium
E) All of the above

Question 66

What result will occur in the coagulation cascade if there is a deficiency of any one of the coagulation factors?

A) Coagulation will not proceed at the normal rate.
B) Initiation of the next subsequent reaction is delayed.
C) The time required for the clot to form is prolonged.
D) Bleeding from the injured vessel continues for a longer time.
E) All of the above

Question 67

All of the following are characteristics of the fibrinogen group of coagulation proteins except:

A) High-molecular-weight proteins.
B) Factors are not absorbed by BaSO₄.
C) Factors are consumed during the coagulation process.
D) Factors V and VIII are the most stabile and therefore present in stored plasma.
E) Factors are increased during inflammation and pregnancy.

Question 68

Fitzgerald factor corresponds to __________.

A) Prothrombin
B) Prekallikrein
C) Fibrinogen
D) High-molecular-weight kininogen
E) None of the above

Question 69

Blood coagulation leading to fibrin formation is separated into the __________ and __________ pathways.

A) Intracorpuscular/extracorpuscular
B) Intramedullary/extramedullary
C) Intravascular/extravascular
D) Extrinsic/intrinsic
E) None of the above

Question 70

All of the following coagulation proteins make up the fibrinogen group except:

A) Factor V
B) Factor I
C) Factor VIII
D) Factor XIII
E) Factor XII

Question 71

The contact group of coagulation proteins includes all of the following except:

A) Hageman factor
B) Plasma thromboplastin antecedent
C) Stuart-Prower factor
D) Prekallikrein
E) High-molecular-weight kininogen

Question 72

All of the following events occur in the extrinsic pathway except:

A) Factor VII is activated to factor VIIa in the presence of calcium and tissue factor.
B) Factors VII, IV, and III activate factor X to Xa.
C) Thrombin generated enhances factors V and VIII to accelerate the intrinsic pathway.
D) Collagen activates factor XII to XIIa.
E) None of the above.

Question 73

What statement best describes the process of blood coagulation?

A) A series of biochemical reactions that transforms circulating blood into an insoluble gel through conversion of fibrin to fibrinogen
B) A series of biochemical reactions that transforms circulating blood into an insoluble gel through conversion of fibrinogen to fibrin
C) The interaction of phospholipids and calcium on the platelet membrane resulting in aggregation.
D) The interaction of phospholipids and thrombin on the platelet membrane resulting in adhesion
E) None of the above

Question 74

Hageman factor corresponds to __________.

A) Factor Xb, factor I
B) Factor II
C) Factor XII
D) None of the above

Question 75

Which are cofactors in the blood coagulation system?

A) Factor III
B) Factor V
C) Factor VIII
D) Fitzgerald factor
E) All of the above

Question 76

The activation of __________ acts as the common link between the fibrinolytic system, the kinin system, and the complement system.

A) Factor XI
B) Factor X
C) Factor XII
D) Factor V
E) Factor III

Question 77

Which additional factors are required to enhance or amplify the contact factors involved in the intrinsic system?

A) Fletcher factor/Fitzgerald factor
B) Fletcher factor/Stuart-Prower factor
C) Christmas factor/Fletcher factor
D) Hageman factor/Christmas factor
E) None of the above

Question 78

Characteristics of the contact group of coagulation proteins include:

A) Function in the initial phase of the intrinsic activation of coagulation
B) Factors are not consumed during coagulation
C) Factors are not absorbed by barium sulfate (BaSO₄)
D) Factors are not vitamin K dependent
E) All of the above

Question 79

The major portion of factor VIII is considered to be a carrier protein called __________.

A) Hageman factor
B) von Willebrand factor
C) Stuart-Prower factor
D) Christmas factor
E) Kinin factor

Question 80

Which coagulation protein exclusively functions to create covalent bonds between the fibrin monomers formed during the coagulation process to form a stable fibrin clot?

A) Factor II
B) Factor XIII
C) Factor XII
D) Factor IX
E) Factor III