Master Physiology in Hemostasis for your laboratory certification exam with our comprehensive collection of 64 multiple-choice questions (MCQs). Focused exclusively on Physiology, these practice questions align with the latest syllabi of ASCP MLS, AMT MLT/MT, AIMS, CSMLS, IBMS, HAAD/DOH, DHA, and MOH exams. Each MCQ includes detailed explanations and references to reinforce key concepts. Sharpen your critical thinking, identify knowledge gaps, and build speed with exam-style questions—all for free. Ideal for targeted revision!
64 MCQs (346-409):
- Which regulatory molecules primarily cause vasoconstriction?
a) Fibrinogen and vWF
b) ADP and EPI
c) Thromboxane A2 and serotonin
d) Collagen and actomyosin - Warfarin therapy affects which coagulation factors?
a) VIII, IX, and X
b) I, II, V, and VII
c) II, VII, IX, and X
d) II, V, and VII - In warfarin therapy, the first factor to decrease is:
a) Factor II
b) Factor V
c) Factor VII
d) Factor VIII - A patient with normal aPTT but prolonged PT and no medications likely has a deficiency in:
a) Factor II
b) Factor V
c) Factor VII
d) Factor VIII - Hageman factor (XII) is involved in all EXCEPT:
a) Activation of C1 to C1 esterase
b) Activation of plasminogen
c) Activation of factor XI
d) Conversion of fibrinogen to fibrin - The strongest plasminogen activator in the contact phase is:
a) Kallikrein
b) Streptokinase
c) HMWK
d) Fibrinogen - Plasminogen → plasmin conversion for fibrin degradation is primarily driven by:
a) PAI-1
b) Alpha-2 antiplasmin
c) tPA
d) Alpha-2 macroglobulin - Tissue factor pathway inhibitor (TFPI) blocks coagulation by:
a) Inhibiting TF-FVIIa-FXa complex
b) Converting thrombin → prothrombin
c) Disrupting FXIII-dependent fibrin crosslinking
d) Masking tissue factor on endothelium - A key inhibitor of plasmin activity is:
a) tPA
b) PAI-1
c) Alpha-2 antiplasmin
d) Plasminogen - Antithrombin (AT) primarily inhibits:
a) IIa and Xa
b) Va and VIIIa
c) VIIa and XIIa
d) IXa and Va - The propagation phase of coagulation involves:
a) A thrombin burst
b) Platelet activation
c) Thrombin feedback
d) Activation of FVa and FVIIIa - In the cell-based coagulation model, the intrinsic pathway acts on:
a) Activated platelets for thrombin burst
b) TF-bearing cells to initiate coagulation
c) Fibrinogen proteolysis
d) Contact pathway activation - Apixaban (oral anticoagulant) directly inhibits:
a) Vitamin K-dependent factors
b) Factor IIa
c) Factor Xa
d) Both IIa and Xa - Which anticoagulant directly inhibits thrombin?
a) LMWH
b) Argatroban
c) Warfarin
d) Rivaroxaban - In renal impairment, which DOAC should be avoided?
a) Dabigatran
b) Apixaban
c) Rivaroxaban
d) Warfarin - Inactive proenzymes in coagulation are called:
a) Serine proteases
b) Cofactors
c) Zymogens
d) Substrates - Platelet alpha granules are located in the:
a) Peripheral zone
b) Sol-gel zone
c) Organelle zone
d) Membranes - The correct sequence of hemostasis is:
a) ↓ Heart rate → platelet adhesion → plug formation
b) Platelet aggregation → FXIII → fibrin plug
c) Vasoconstriction → platelet aggregation → fibrin formation
d) Vascular damage → stasis → endothelial injury - The platelet collagen receptor is:
a) GPIb/IX/V complex
b) GPIIb/IIIa complex
c) GPIa/IIa complex
d) GPIV/IX complex - The platelet fibrinogen receptor is:
a) GPIb/IX
b) GPIIb/IIIa
c) GPIa/IIa
d) GPIc/IIa - GP1b activation in vivo and in vitro relies on:
a) Shear force (in vivo); ristocetin (in vitro)
b) Ristocetin (in vivo); compression (in vitro)
c) ADP receptor (in vivo); ristocetin (in vitro)
d) vWF binding (in vivo); epinephrine (in vitro) - Aspirin impairs platelet function by:
a) Inactivating cyclooxygenase (blocks thromboxane A2)
b) Inhibiting vWF via GPIb/IX
c) Reducing arachidonic acid
d) Inactivating ADP and phospholipase A2 - In factor V Leiden mutation, FV activity is typically:
a) Shortened
b) Prolonged
c) Undetectable
d) Within reference range - The ISI (International Sensitivity Index) is determined using:
a) Rabbit thromboplastin
b) Micronized silica
c) Tissue factor
d) Human brain thromboplastin - A coagulation reagent is sensitive to a factor deficiency if it detects activity below:
a) 30%
b) 40%
c) 50%
d) 60% - Heat-labile coagulation factors are:
a) II and IX
b) V and VIII
c) VII and XI
d) X and XII - The carrier protein for factor VIII is:
a) Factor V
b) Factor IX
c) Tissue factor
d) von Willebrand factor (vWF) - Patients may present with bleeding OR thrombosis in:
a) Dysfibrinogenemia
b) Hypofibrinogenemia
c) Afibrinogenemia
d) Hyperfibrinogenemia - The key enzyme in fibrinolysis is:
a) Plasmin
b) Thrombin
c) Urokinase
d) Streptokinase - The major serine protease for clot breakdown is:
a) tPA
b) Alpha-2 antiplasmin
c) Streptokinase
d) PAI-1 - The subendothelial protein that triggers coagulation via FVII activation is:
a) Thrombomodulin
b) Nitric oxide
c) Tissue factor (TF)
d) Silica
- Protein C + protein S inactivate:
a) IIa and Xa
b) Va and VIIIa
c) VIIa and IXa
d) XIa and XIIa - What initiates primary hemostasis?
a) Fibrin clot formation
b) Platelet adhesion
c) Vasoconstriction
d) Thrombin activation - Which substance is essential for platelet adhesion to subendothelial collagen?
a) Thromboxane A2
b) Factor VIII
c) von Willebrand factor
d) Platelet factor 4 - Which platelet receptor binds to von Willebrand factor?
a) GPIIb/IIIa
b) GPVI
c) GPIb/IX
d) GPIa/IIa - What platelet membrane receptor is responsible for fibrinogen binding?
a) GPIb/IX
b) GPIIb/IIIa
c) GPVI
d) PAR-1 - What is the role of thromboxane A2 in hemostasis?
a) Activates fibrin
b) Dilates blood vessels
c) Promotes platelet aggregation and vasoconstriction
d) Inhibits platelet function - Dense granules of platelets contain all EXCEPT:
a) ADP
b) ATP
c) Calcium
d) Fibrinogen - Which substance is secreted from platelet alpha granules?
a) Calcium
b) ATP
c) Serotonin
d) Platelet-derived growth factor - Which factor stabilizes fibrin in the clot?
a) Factor XIII
b) Factor XII
c) Factor XI
d) Factor X - Which coagulation factor is also known as anti-hemophilic factor A?
a) Factor VII
b) Factor VIII
c) Factor IX
d) Factor XI - Factor IX is also known as:
a) Stuart-Prower factor
b) Hageman factor
c) Christmas factor
d) Anti-hemophilic factor A - The intrinsic pathway is initiated by:
a) Exposure to tissue factor
b) Platelet adhesion
c) Exposure to collagen
d) Thrombin burst - Tissue factor is required for activation of:
a) Factor VII
b) Factor IX
c) Factor XI
d) Factor XII - The common pathway begins with activation of:
a) Factor VII
b) Factor IX
c) Factor X
d) Factor XII - What complex activates Factor X in the intrinsic pathway?
a) IXa-VIIIa complex
b) TF-VIIa complex
c) Va-Xa complex
d) XIa-XIIa complex - Which enzyme converts fibrinogen to fibrin?
a) Factor X
b) Thrombin
c) Plasmin
d) Factor XIII - What is the function of antithrombin?
a) Degrades fibrin
b) Activates thrombin
c) Inhibits thrombin and other proteases
d) Enhances platelet aggregation - What enhances antithrombin activity?
a) Vitamin K
b) Protein C
c) Heparin
d) Calcium - Protein C inactivates which clotting factors?
a) II and V
b) V and VIII
c) VII and IX
d) X and XI - What cofactor is needed by protein C?
a) Antithrombin
b) Vitamin K
c) Protein S
d) Factor V - What is the role of plasmin?
a) Initiates coagulation
b) Converts prothrombin to thrombin
c) Inhibits thrombin
d) Degrades fibrin - What activates plasminogen to plasmin?
a) Thrombin
b) tPA
c) Factor XIIa
d) Protein C - Which test evaluates platelet function?
a) PT
b) aPTT
c) Bleeding time
d) Fibrinogen assay - Which test is prolonged in Hemophilia A?
a) PT
b) aPTT
c) Bleeding time
d) Thrombin time - Which vitamin is required for synthesis of coagulation factors II, VII, IX, X?
a) Vitamin B12
b) Vitamin D
c) Vitamin K
d) Vitamin A - The extrinsic pathway is assessed by which test?
a) PT
b) aPTT
c) TT
d) Platelet count - Thrombin time evaluates:
a) Fibrinogen to fibrin conversion
b) Factor VIII deficiency
c) Platelet function
d) Factor VII activation - Which is a primary inhibitor of fibrinolysis?
a) Heparin
b) Antithrombin
c) α2-antiplasmin
d) Protein C - Which factor is not vitamin K-dependent?
a) Factor IX
b) Factor VII
c) Factor VIII
d) Factor X - What does thrombin activate?
a) Platelets
b) Factor XIII
c) Protein C
d) All of the above - Which is a natural anticoagulant?
a) Fibrinogen
b) Plasmin
c) Antithrombin
d) Factor XIII - Platelet activation results in all EXCEPT:
a) Shape change
b) Granule release
c) Vasodilation
d) Aggregation - Phospholipids on activated platelets provide surface for:
a) Protein C synthesis
b) Fibrinolysis
c) Coagulation complex assembly
d) von Willebrand factor production
Answer Key
Answer Key:
- c) Thromboxane A2 and serotonin
- c) II, VII, IX, and X
- c) Factor VII
- c) Factor VII
- d) Conversion of fibrinogen to fibrin
- a) Kallikrein
- c) tPA
- a) Inhibiting TF-FVIIa-FXa complex
- c) Alpha-2 antiplasmin
- a) IIa and Xa
- a) A thrombin burst
- a) Activated platelets for thrombin burst
- c) Factor Xa
- b) Argatroban
- a) Dabigatran
- c) Zymogens
- c) Organelle zone
- c) Vasoconstriction → platelet aggregation → fibrin formation
- c) GPIa/IIa complex
- b) GPIIb/IIIa
- a) Shear force (in vivo); ristocetin (in vitro)
- a) Inactivating cyclooxygenase (blocks thromboxane A2)
- d) Within reference range
- a) Rabbit thromboplastin
- a) 30%
- b) V and VIII.
- d) von Willebrand factor (vWF)
- a) Dysfibrinogenemia
- a) Plasmin
- a) tPA
- b) Factor VIII
- c) Christmas factor
- c) Exposure to collagen
- a) Factor VII
- c) Factor X
- a) IXa-VIIIa complex
- b) Thrombin
- c) Inhibits thrombin and other proteases
- c) Heparin
- b) V and VIII
- d) All of the above
- c) Antithrombin
- c) Vasodilation
- c) Coagulation complex assembly
- c) Tissue factor (TF)
- b) Va and VIIIa
- b) Platelet adhesion
- c) von Willebrand factor
- c) GPIb/IX
- b) GPIIb/IIIa
- c) Promotes platelet aggregation and vasoconstriction
- d) Fibrinogen
- d) Platelet-derived growth factor
- a) Factor XIII
- c) Protein S
- d) Degrades fibrin
- b) tPA
- c) Bleeding time
- b) aPTT
- c) Vitamin K
- a) PT
- a) Fibrinogen to fibrin conversion
- c) α2-antiplasmin
- c) Factor VIII
Top 8 Medical Laboratory Scientist (MLS) Exams:
Top 8 Medical Laboratory Scientist (MLS) Exams that are recognized globally and can help professionals validate their credentials and enhance their career opportunities:
1. ASCP – American Society for Clinical Pathology (USA)
- Exam Name: MLS(ASCP)
- Eligibility: Bachelor’s degree with clinical laboratory experience.
- Global Recognition: High
- Purpose: Certifies Medical Laboratory Scientists in the United States and internationally.
2. AMT – American Medical Technologists (USA)
- Exam Name: MLT(AMT) or MT(AMT)
- Eligibility: Academic and/or work experience in medical laboratory technology.
- Global Recognition: Moderate
- Purpose: Credentialing for medical technologists and technicians.
3. AIMS – Australian Institute of Medical and Clinical Scientists
- Exam Name: AIMS Certification Exam
- Eligibility: Assessment of qualifications and work experience.
- Recognition: Required for practice in Australia.
- Purpose: Certification and registration in Australia.
4. CSMLS – Canadian Society for Medical Laboratory Science
- Exam Name: CSMLS General or Subject-specific Exams
- Eligibility: Graduation from a CSMLS-accredited program or equivalent.
- Recognition: Canada
- Purpose: Entry-to-practice certification in Canada.
5. IBMS – Institute of Biomedical Science (UK)
- Exam Name: Registration and Specialist Portfolio Assessment
- Eligibility: Accredited degree and lab experience.
- Recognition: UK and some Commonwealth countries.
- Purpose: Biomedical Scientist registration with the HCPC (UK).
6. HAAD / DOH – Department of Health, Abu Dhabi (UAE)
- Exam Name: DOH/HAAD License Exam
- Eligibility: Degree in medical laboratory science and experience.
- Recognition: UAE (Abu Dhabi)
- Purpose: Licensure for medical laboratory practice in Abu Dhabi.
7. DHA – Dubai Health Authority (UAE)
- Exam Name: DHA License Exam for Medical Laboratory Technologists
- Eligibility: Relevant degree and experience.
- Recognition: Dubai, UAE
- Purpose: Professional license for clinical laboratory practice in Dubai.
8. MOH – Ministry of Health (Gulf Countries like UAE, Saudi Arabia, Kuwait)
- Exam Name: MOH License Exam
- Eligibility: BSc/Diploma in Medical Laboratory + experience.
- Recognition: Varies by country.
- Purpose: Required for practicing in public and private sector labs.
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