Physiology Flashcards
Vasoconstriction is caused by several regulatory molecules, which include:
a) fibrinogen and vWF
b) ADP and EPI
c) thromboxane A2 and serotonin
d) collagen and actomyosin
c)
Thromboxane A2 promotes platelet aggregation and vasoconstriction. Serotonin released from the dense bodies of platelets is a vasoconstrictor that binds endothelial cells and platelet membranes.
Warfarin is classified as a vitamin K antagonist. The factors that are impacted by warfarin therapy are:
a) VII, IX, and X
b) I, II, V, and VII
c) II, VII, IX, and X
d) II, V and VII
c. II, VII, IX, and X
When a patient is placed on warfarin therapy , the first factors that will be decreased is:
a) factor I
b) factor V
c) factor VII
d) factor VIII
c.
Factor VII (proconvertin) has the shortest half life of 6 hours and will therefore be decreased first.
A patient with a positive family history of bleeding presents to the ED with the results below.
Test Result Reference range
aPTT 29.5s 25-35 s
PT 19.2 s 10.5-12.5 s
The patient is not on any medication and so is likely to be deficient in factor:
a) II
b) V
c) VII
d) VIII
c. VII
Factor VII is the only factor found in the extrinsic pathway and is the most likeley.
Hageman factor (XII) is involved in each of the following reactions except:
a) activation of C1 to C1 esterase
b) activation of plasminogen
c) activation of factor XI
d) transformation of fibrinogen to fibrin
d.
Fibrinogen is converted to fibrin by the action of thrombin.
The most potent plasminogen activator in the contact phase of coagulation in:
a) kallikrein
b) streptokinase
c) HMWK
d) fibrinogen
a) kallikrein
The activation of plasminogen to plasmin resulting in the degradation of fibrin occurs by:
a) PAI-1
b) alpha-2 antiplasmin
c) tPA
d) alpha-2 macroglobulin
c)
tPA converts plasminogen to plasmin. tPA is released as a result of the activity of endothelial damage and the production of thrombin.
How does tissue factor pathway inhibitor inhibit coagulation?
inhibition of tissue factor-factor VIIa-factor Xa complex
An inhibitor of plasmin activity is:
a) tPA
b) PAI-1
c) alpha-2 antiplasmin
d) plasminogen
c.
alpha-2 antiplasmin is synthesized in the liver and is the primary inhibitor of free plasmin.
Anti-thrombin inhibits factors:
a) IIa and Xa
b) Va and VIIIa
c) VIIa and XIIa
d) IXa and Va
a)
IIa and Xa
The propagation phase of the in vivo coagulation model includes:
a) a final burst of thrombin
b) activation of platelets
c) feedback mechanism to thrombin
d) activation of factor Va and factor VIIIa
a)
In the cell-based model of coagulation the intrinsic pathway operates on the:
a) activated platelet surface to produce the burst of thrombin
b) tissue factor bearing cell to initiate and amplify coagulation
c) proteolytic digestion of fibrinogen
d) activation of the contact pathway
a)
model states that the intrinsic pathway is said to occur on the platelet surface.
A new oral anticoagulant apixaban has been given to a patient who was previously on warfarin. This drug directly inhibits:
a) vitamin-k-dependent factors
b) factor IIa
c) Xa
d) both factor IIa and Xa
c) Xa
Note:
Apixaban is an oral direct anti-FXa inhibitor used to prevent VTE.
The anticoagulant that directly inhibits thrombin is:
a) LMWH
b) argatroban
c) warfarin
d) rivorxaban
b)
argatroban
A patient who presents with renal impairment is being started on oral anticoagulant therapy. The DOAC that should be avoided would be:
a) dabigatran
b) apixaban
c) rivaroxaban
d) warfarin
a) dabigatran
In secondary hemostasis, coagulation proteins become activated to form a fibrin clot. Prior to these proteins being activated, their inactive proenzymes are known as:
a) serine proteases
b) cofactors
c) zymogens
d) substrates
c) zymogens
Alpha granules are found on the platelet in the:
a) peripheral zone
b) sol gel zone
c) organelle zone
d) membranes
c)
Organelle zone contains alpha, dense and lysosome granules.
Which of the following best represents the 3 steps of normal hemostasis (in order)?
a) decreased heart rate, adhesion of platelets, plug formation
b) platelet aggregation, formation of FXII, fibrin plug
c) vasoconstriction, platelet aggregation, fibrin formation
d) vascular damage, stasis, endothelial injury
c)
vasoconstriction, platelet aggregation, fibrin formation
Which of the following platelet antigens is the receptor for collagen?
a) GPIb/V/IX complex
b) GPIIb/IIIa complex
c) GPIa/IIa complex
d) GPIc/IIa complex
c)
GPIa/IIa complex
Which platelet surface antigen acts as the receptor for fibrinogen?
a) GPIb/V/IX
b) GPIIb/IIIa
c) GPIa/IIa
d) GPIc/IIa
b)
GPIIb/IIIa
How does GPIb become activated in vivo and in vitro, respectively?
a) shear force, ristocetin
b) ristocetin, compression
c) activation of ADP receptor, ristocetin
d) binding vWF, epinephrine
a)
shear force, ristocetin
A patient is on aspirin 100 mg/day to prevent the formation of clots caused by platelets. The mechanism in which aspirin impairs platelet function is by:
a) inactivating cyclooxygenase which blocks thromboxane A2
b) impairs vWF by via GPIb/IX/V receptor
c) decreased amounts of arachidonic acid
d) inactivation of ADP and phospholipase A2
a)
inactivating cyclooxygenase which blocks thromboxane A2
A patient is diagnosed with factor V Leiden mutation. The factor V activity level should be:
a) shortened
b) prolonged
c) undetectable
d) within reference range
d)
within reference range
The International Sensitivity Index (ISI) is determined by comparing the PT results of the manufacturer’s reagent against:
a) rabbit thromboplastin
b) micronized silica
c) tissue factor
d) human brain thromboplastin
d)
human brain thromboplastin
A coagulation reagent should be sensitive to factor deficiencies. A reagent is considered sensitive to a factor when the level of factor activity is approximately:
a) 30%
b) 40%
c) 50%
d) 60%
a)
30%
What factors are considered heat labile?
a) II and IX
b) V and VIII
c) VII and XI
d) X and XII
b)
V and VIII
What factor serves as a carrier for factor VIII?
a) factor V
b) factor IX
c) tissue factor
d) von Willebrand factor
d)
von Willebrand factor
Patients may present with either a bleeding or a thrombotic event in:
a) dysfibrinogenemia
b) hypofibrinogenemia
c) afibrinogenemia
d) hyperfibrinogenemia
a)
dysfibrinogenemia
The key enzyme of the fibrinolytic system is:
a) Plasmin
b) thrombin
c) urokinase
d) streptokinase
a)
Plasmin
The major serine protease responsible for clot breakdown is:
a) TPA
b) alpha 2 antiplasmin
c) streptokinase
d) PAI-1
a)
Tissue plasminogen activator
What subendothelial structural protein triggers coagulation through activation of FVII?
a) thrombomodulin
b) nitric oxide
c) tissue factor
d) silica
c)
tissue factor
Protein C and its cofactor protein S proteolytically inactivate factors:
a) IIa and Xa
b) Va and VIIIa
c) VIIIa and IXa
d) XIa and XIIa
b)
Va and VIIIa
