Coagulation and Haemostasis Practice Questions
20 free Coagulation and Haemostasis practice questions for the Physiology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which is the first step in hemostasis following vascular injury?
- A Coagulation cascade activation
- B Platelet aggregation
- C Vasoconstriction
- D Fibrin formation
Correct answer: Vasoconstriction
Vasoconstriction occurs immediately after vessel injury to reduce blood loss. It is mediated by local factors and neural reflexes.
Primary hemostasis mainly involves:
- A Platelet plug formation
- B Fibrin clot formation
- C Activation of clotting factors
- D Plasmin activity
Correct answer: Platelet plug formation
Primary hemostasis involves platelet adhesion, activation, and aggregation to form a temporary platelet plug.
Which factor initiates the extrinsic pathway of coagulation?
- A Factor XII (Hageman)
- B Factor VIII (Antihemophilic)
- C Tissue factor (Factor III)
- D Factor IX (Christmas)
Correct answer: Tissue factor (Factor III)
The extrinsic pathway begins when tissue factor is released from damaged tissues and activates factor VII.
Which clotting factor is activated first in the intrinsic pathway?
- A Factor XII
- B Factor X
- C Factor V
- D Factor VII
Correct answer: Factor XII
The intrinsic pathway starts with activation of factor XII when blood contacts a negatively charged surface.
Which factor is common to both intrinsic and extrinsic pathways?
- A Factor VII
- B Factor XII
- C Factor X (Stuart factor)
- D Factor VIII (Antihemophilic factor)
Correct answer: Factor X (Stuart factor)
Factor X is the convergence point of intrinsic and extrinsic pathways, leading into the common pathway.
Which substance stabilizes the platelet plug during coagulation?
- A Fibrin strands
- B Thrombin enzyme
- C Calcium ions
- D Plasmin enzyme
Correct answer: Fibrin strands
Fibrin forms a mesh that strengthens and stabilizes the platelet plug, creating a firm clot.
Which enzyme converts prothrombin to thrombin?
- A Factor X
- B Factor IX
- C Factor V
- D Factor VIII
Correct answer: Factor X
Activated factor X, along with factor V, converts prothrombin into thrombin in the common pathway.
Which ion is essential for multiple steps in the coagulation cascade?
- A Sodium
- B Potassium
- C Calcium
- D Chloride
Correct answer: Calcium
Calcium ions act as cofactors in several steps of the coagulation cascade and are necessary for clot formation.
Which test evaluates the intrinsic pathway of coagulation?
- A Standard prothrombin clotting time test
- B Simple capillary bleeding time test
- C Activated partial thromboplastin time
- D Full platelet count blood test
Correct answer: Activated partial thromboplastin time
aPTT assesses the intrinsic and common pathways by measuring clotting time after activation of factor XII.
Which protein is activated by thrombin to stabilize fibrin?
- A Factor II
- B Factor V
- C Factor VIII
- D Factor XIII
Correct answer: Factor XIII
Factor XIII cross-links fibrin strands, stabilizing the clot and making it more resistant to breakdown.
Which process breaks down fibrin clots after healing?
- A Fibrinolysis
- B Coagulation
- C Hemolysis
- D Platelet aggregation
Correct answer: Fibrinolysis
Fibrinolysis involves the breakdown of fibrin by plasmin, allowing removal of the clot after repair.
Which enzyme is responsible for fibrinolysis?
- A Thrombin
- B Plasmin
- C Fibrin
- D Prothrombin
Correct answer: Plasmin
Plasmin degrades fibrin into soluble products, dissolving the clot during fibrinolysis.
Which anticoagulant is naturally present in the body?
- A Aspirin
- B Heparin
- C Warfarin
- D Clopidogrel
Correct answer: Heparin
Heparin is a natural anticoagulant that enhances antithrombin III activity, preventing clot formation.
Which protein inhibits thrombin and factor Xa activity?
- A Fibrinogen
- B Antithrombin III
- C Complement protein C3
- D Hemoglobin
Correct answer: Antithrombin III
Antithrombin III inhibits key clotting enzymes like thrombin and factor Xa, regulating coagulation.
Which step follows platelet adhesion in primary hemostasis?
- A Fibrin formation
- B Platelet activation
- C Coagulation cascade
- D Clot retraction
Correct answer: Platelet activation
After adhesion, platelets become activated, releasing substances that promote aggregation.
Which substance released by platelets enhances aggregation?
- A PGI2
- B ADP
- C NO
- D Heparin
Correct answer: ADP
ADP released from platelets promotes further platelet activation and aggregation.
Which factor is most important for initiating fibrinolysis?
- A Alpha-2-antiplasmin
- B Tissue plasminogen activator
- C Plasminogen activator inhibitor-1
- D Kallikrein
Correct answer: Tissue plasminogen activator
Tissue plasminogen activator converts plasminogen to plasmin, initiating fibrinolysis.
Which condition results from deficiency of multiple clotting factors?
- A von Willebrand disease
- B Thrombocytopenia
- C Polycythemia
- D Vitamin K deficiency
Correct answer: Vitamin K deficiency
Vitamin K deficiency affects synthesis of several clotting factors, leading to impaired coagulation.
Which process helps reduce the size of a clot after formation?
- A Platelet adhesion
- B Fibrinolysis
- C Aggregation
- D Clot retraction
Correct answer: Clot retraction
Clot retraction involves contraction of platelets, reducing clot size and strengthening it.
Which step represents the final outcome of the coagulation cascade?
- A Platelet aggregation
- B Thrombin activation
- C Calcium release
- D Fibrin formation
Correct answer: Fibrin formation
The final step of coagulation is the formation of a fibrin mesh that stabilizes the clot.