Question 1

Which factor helps prevent platelet adhesion by maintaining the smoothness of the endothelial cell surface?
A) Thrombomodulin
B) Glycocalyx
C) Protein C
D) Antithrombin III
E) Heparin

Accepted Answer

B) Glycocalyx
Explanation: Glycocalyx helps to prevent platelet adhesion by maintaining the smoothness of the endothelial cell surface, thus preventing the initiation of the coagulation cascade.

Question 2

What is the role of the tenase complex in the coagulation process?
A) It converts Factor X into Factor Xa
B) It converts prothrombin to thrombin
C) It forms the prothrombinase complex
D) It activates Factor V
E) It degrades fibrin fibers

Accepted Answer

A) It converts Factor X into Factor Xa
Explanation: The tenase complex, composed of Factor IXa, Factor VIIIa, and Ca²⁺, converts Factor X into Factor Xa, which is a critical step in the coagulation cascade.

Question 3

What is the function of thrombin in the coagulation process?
A) It converts fibrinogen into fibrin fibers
B) It activates Factor XII
C) It forms the tenase complex
D) It degrades fibrin fibers
E) It converts plasminogen to plasmin

Accepted Answer

A) It converts fibrinogen into fibrin fibers
Explanation: Thrombin acts as an enzyme to convert fibrinogen into fibrin fibers, which enmesh platelets, blood cells, and plasma to form the clot.

Question 4

Which factors are involved in the extrinsic pathway of coagulation?
A) Factors XII, XI, IX
B) Factors III, VII, X
C) Factors V, VIII, IX
D) Factors II, V, X
E) Factors I, II, V

Accepted Answer

B) Factors III, VII, X
Explanation: The extrinsic pathway involves Factors III, VII, and X, which are crucial for the cascade of protease reactions initiated by factors outside the vascular system.

Question 5

What role does kallikrein play in the intrinsic pathway of coagulation?
A) It converts Factor XI to XIa
B) It transforms prekallikrein into kallikrein
C) It enhances the conversion of Factor XII into XIIa
D) It activates Factor IX
E) It forms the tenase complex

Accepted Answer

C) It enhances the conversion of Factor XII into XIIa
Explanation: Kallikrein enhances the conversion of Factor XII into XIIa through positive feedback, which is a crucial step in the intrinsic pathway of coagulation.

Question 6

What is the primary role of anticoagulants in the body?
A) To promote blood clotting
B) To oppose or limit coagulation
C) To increase platelet adhesion
D) To enhance fibrin formation
E) To decrease blood flow

Accepted Answer

B) To oppose or limit coagulation
Explanation: Anticoagulants are substances that oppose or limit coagulation to restore the clot-free condition of the blood after the damaged vascular walls heal.

Question 7

Which anticoagulant forms a complex with thrombin to remove it from circulation?
A) Prostacyclin
B) Nitric oxide
C) Tissue factor pathway inhibitor (TFPI)
D) Thrombomodulin
E) Heparin

Accepted Answer

D) Thrombomodulin
Explanation: Thrombomodulin forms a complex with thrombin to remove thrombin from the circulation, thereby inhibiting coagulation.

Question 8

Which factor is considered the most important for targeted therapy in the coagulation process?
A) Factor V
B) Factor X
C) Factor VII
D) Factor III
E) Factor XII

Accepted Answer

B) Factor X
Explanation: Factor X, also known as Stuart factor, is highlighted as the most important factor for targeted therapy in the coagulation process.

Question 9

What is the purpose of the Prothrombin Time (PT) test?
A) To measure the concentration of fibrinogen in the blood
B) To determine the concentration of prothrombin in the blood
C) To assess platelet function
D) To measure white blood cell count
E) To evaluate red blood cell count

Accepted Answer

B) To determine the concentration of prothrombin in the blood
Explanation: The Prothrombin Time (PT) test is used to indicate the concentration of prothrombin in the blood and the time required for coagulation to take place.

Question 10

Which pathway is initiated by contact with negatively charged phospholipids?
A) Extrinsic pathway
B) Intrinsic pathway
C) Common pathway
D) Fibrinolytic pathway
E) Platelet pathway

Accepted Answer

B) Intrinsic pathway
Explanation: The intrinsic pathway is initiated by contact with negatively charged phospholipids, leading to the activation of factor XII and subsequent factors in the coagulation cascade.

Question 11

What is the role of Protein S in the anticoagulation process?
A) Promotes vasodilation
B) Acts as a cofactor for Protein C
C) Inhibits platelet adhesion
D) Binds to and inhibits Factor Xa
E) Blocks protease activity for Factor VIIa

Accepted Answer

B) Acts as a cofactor for Protein C
Explanation: Protein S acts as a cofactor in the function of Protein C, which inactivates clotting factors involved in the intrinsic pathway.

Question 12

What does a high INR value indicate?
A) High risk of clotting
B) High risk of bleeding
C) Normal coagulation
D) Low risk of bleeding
E) Low risk of clotting

Accepted Answer

B) High risk of bleeding
Explanation: A high INR value indicates a high risk of bleeding, as it suggests that the blood is taking longer than normal to clot.

Question 13

What is the function of high-molecular-weight kininogen (HMWK) in the intrinsic pathway?
A) To activate Factor X
B) To act as a cofactor and anchor Factor XII to the surface
C) To convert prothrombin into thrombin
D) To release Tissue Factor III
E) To form a fibrin clot

Accepted Answer

B) To act as a cofactor and anchor Factor XII to the surface
Explanation: HMWK acts as a cofactor, helping anchor Factor XII to the surface, facilitating its activation in the intrinsic pathway.

Question 14

What is the normal range for INR (International Normalized Ratio)?
A) 0.5 to 1.0
B) 0.9 to 1.3
C) 1.5 to 2.0
D) 2.0 to 3.0
E) 3.0 to 4.0

Accepted Answer

B) 0.9 to 1.3
Explanation: The normal range for INR is 0.9 to 1.3, which helps standardize the measurements of prothrombin time across different laboratories.

Question 15

What is the function of antithrombin in the control of coagulation?
A) Activates factor X
B) Converts fibrinogen to fibrin
C) Inhibits thrombin
D) Activates factor IX
E) Stabilizes fibrin strands

Accepted Answer

C) Inhibits thrombin
Explanation: Antithrombin functions to inhibit thrombin, thereby preventing excessive clot formation and helping to regulate the coagulation process.

Question 16

What is the function of Antithrombin III (ATIII)?
A) Promotes vasodilation
B) Inhibits platelet adhesion
C) Binds to and inhibits Factor Xa and thrombin
D) Blocks protease activity for Factor VIIa
E) Forms a complex with thrombin

Accepted Answer

C) Binds to and inhibits Factor Xa and thrombin
Explanation: Antithrombin III (ATIII) binds to and inhibits Factor Xa and thrombin, playing a crucial role in preventing excessive blood clotting.

Question 17

What initiates the process of fibrinolysis?
A) Conversion of prothrombin to thrombin
B) Activation of Factor XII
C) Conversion of plasminogen to plasmin
D) Formation of the tenase complex
E) Activation of Factor V

Accepted Answer

C) Conversion of plasminogen to plasmin
Explanation: Fibrinolysis begins with the conversion of plasminogen to plasmin, which is catalyzed by tissue plasminogen activator or urokinase-type plasminogen activator.

Question 18

Which factor, along with HMWK, cleaves Factor XI into Factor XIa?
A) Factor IXa
B) Factor XIIa
C) Factor VIIIa
D) Factor Xa
E) Factor Va

Accepted Answer

B) Factor XIIa
Explanation: Factor XIIa, along with High-Molecular-Weight Kininogen (HMWK), cleaves Factor XI into Factor XIa, which is an important step in the intrinsic pathway.

Question 19

What triggers the intrinsic pathway of coagulation?
A) Trauma to the vascular wall
B) Contact with negatively charged surfaces
C) Release of Tissue Factor III
D) Activation of Factor VII
E) Formation of a prothrombin activator

Accepted Answer

B) Contact with negatively charged surfaces
Explanation: The intrinsic pathway is triggered by contact with negatively charged surfaces, such as nucleic acids and phospholipids.

Question 20

Which anticoagulant is used for bypass surgery and pulmonary embolism due to its short-acting nature?
A) Prostacyclin
B) Nitric oxide
C) Heparin
D) Antithrombin III
E) Thrombomodulin

Accepted Answer

C) Heparin
Explanation: Heparin is a short-acting anticoagulant that lasts about 1 ½ to 4 hours and is used for bypass surgery and pulmonary embolism.

Question 21

What is the role of the prothrombin activator in the coagulation process?
A) To activate Factor XII
B) To convert prothrombin into thrombin
C) To form a fibrin clot
D) To release Tissue Factor III
E) To inhibit thrombin formation

Accepted Answer

B) To convert prothrombin into thrombin
Explanation: The prothrombin activator's role is to convert prothrombin into thrombin, which is a crucial step in the coagulation process.

Question 22

Which complex is responsible for activating Factor X in the intrinsic pathway?
A) VIIa-Tissue Factor-Ca²⁺ complex
B) IXa-VIIIa-Ca²⁺-Phospholipid complex
C) Xa-Va-Phospholipid complex
D) XIIa-HMWK complex
E) Prothrombin activator complex

Accepted Answer

B) IXa-VIIIa-Ca²⁺-Phospholipid complex
Explanation: The IXa-VIIIa-Ca²⁺-Phospholipid complex is responsible for activating Factor X in the intrinsic pathway.

Question 23

Which pathway is initiated by tissue injury and the release of tissue factor (factor III)?
A) Intrinsic pathway
B) Extrinsic pathway
C) Common pathway
D) Fibrinolytic pathway
E) Platelet pathway

Accepted Answer

B) Extrinsic pathway
Explanation: The extrinsic pathway is initiated by tissue injury, which results in the release of tissue factor (factor III), leading to the activation of factor VII and subsequently factor X.

Question 24

What is the main purpose of the common pathway in coagulation?
A) To form the tenase complex
B) To convert fibrinogen into fibrin
C) To form the prothrombin activator
D) To activate Factor XII
E) To degrade the clot

Accepted Answer

C) To form the prothrombin activator
Explanation: The main purpose of the common pathway is to form the prothrombin activator, which then converts prothrombin to thrombin, leading to the conversion of fibrinogen into fibrin.

Question 25

What happens when Factor XII comes into contact with collagen or other negatively charged surfaces?
A) It forms a fibrin clot
B) It releases Tissue Factor III
C) It undergoes a molecular configuration change and activates
D) It inhibits thrombin formation
E) It converts prothrombin into thrombin

Accepted Answer

C) It undergoes a molecular configuration change and activates
Explanation: When Factor XII comes into contact with collagen or other negatively charged surfaces, it undergoes a molecular configuration change, resulting in its activation.

Question 26

Which factor is responsible for converting fibrinogen into fibrin?
A) Factor IXa
B) Factor Xa
C) Thrombin
D) TF/Factor VIIa complex
E) Factor XIII

Accepted Answer

C) Thrombin
Explanation: Thrombin is the enzyme responsible for converting fibrinogen into fibrin, which is essential for clot formation.

Question 27

What initiates the extrinsic pathway of coagulation?
A) Contact with negatively charged surfaces
B) Trauma to the vascular wall
C) Activation of Factor XII
D) Release of Factor VIII
E) Formation of a fibrin clot

Accepted Answer

B) Trauma to the vascular wall
Explanation: The extrinsic pathway begins with a traumatized vascular wall coming into contact with blood, leading to the release of Tissue Factor III (or Tissue Thromboplastin).

Question 28

What is the role of factor XIII in the common pathway?
A) Activates factor X
B) Converts fibrinogen to fibrin
C) Stabilizes fibrin strands
D) Activates factor IX
E) Inhibits thrombin

Accepted Answer

C) Stabilizes fibrin strands
Explanation: Factor XIII stabilizes the fibrin strands formed during the coagulation process, ensuring the stability of the blood clot.

Which factor helps prevent platelet adhesion by maintaining the smoothness of the endothelial cell surface?A) ThrombomodulinB) GlycocalyxC) Protein CD) Antithrombin IIIE) Heparin

What is the role of the tenase complex in the coagulation process?A) It converts Factor X into Factor XaB) It converts prothrombin to thrombinC) It forms the prothrombinase complexD) It activates Factor VE) It degrades fibrin fibers

What is the function of thrombin in the coagulation process?A) It converts fibrinogen into fibrin fibersB) It activates Factor XIIC) It forms the tenase complexD) It degrades fibrin fibersE) It converts plasminogen to plasmin

Which factors are involved in the extrinsic pathway of coagulation?A) Factors XII, XI, IXB) Factors III, VII, XC) Factors V, VIII, IXD) Factors II, V, XE) Factors I, II, V

What role does kallikrein play in the intrinsic pathway of coagulation?A) It converts Factor XI to XIaB) It transforms prekallikrein into kallikreinC) It enhances the conversion of Factor XII into XIIaD) It activates Factor IXE) It forms the tenase complex

What is the primary role of anticoagulants in the body?A) To promote blood clottingB) To oppose or limit coagulationC) To increase platelet adhesionD) To enhance fibrin formationE) To decrease blood flow

Which anticoagulant forms a complex with thrombin to remove it from circulation?A) ProstacyclinB) Nitric oxideC) Tissue factor pathway inhibitor (TFPI)D) ThrombomodulinE) Heparin

Which factor is considered the most important for targeted therapy in the coagulation process?A) Factor VB) Factor XC) Factor VIID) Factor IIIE) Factor XII

What is the purpose of the Prothrombin Time (PT) test?A) To measure the concentration of fibrinogen in the bloodB) To determine the concentration of prothrombin in the bloodC) To assess platelet functionD) To measure white blood cell countE) To evaluate red blood cell count

Which pathway is initiated by contact with negatively charged phospholipids?A) Extrinsic pathwayB) Intrinsic pathwayC) Common pathwayD) Fibrinolytic pathwayE) Platelet pathway

What is the role of Protein S in the anticoagulation process?A) Promotes vasodilationB) Acts as a cofactor for Protein CC) Inhibits platelet adhesionD) Binds to and inhibits Factor XaE) Blocks protease activity for Factor VIIa

What does a high INR value indicate?A) High risk of clottingB) High risk of bleedingC) Normal coagulationD) Low risk of bleedingE) Low risk of clotting

What is the function of high-molecular-weight kininogen (HMWK) in the intrinsic pathway?A) To activate Factor XB) To act as a cofactor and anchor Factor XII to the surfaceC) To convert prothrombin into thrombinD) To release Tissue Factor IIIE) To form a fibrin clot

What is the normal range for INR (International Normalized Ratio)?A) 0.5 to 1.0B) 0.9 to 1.3C) 1.5 to 2.0D) 2.0 to 3.0E) 3.0 to 4.0

What is the function of antithrombin in the control of coagulation?A) Activates factor XB) Converts fibrinogen to fibrinC) Inhibits thrombinD) Activates factor IXE) Stabilizes fibrin strands

What is the function of Antithrombin III (ATIII)?A) Promotes vasodilationB) Inhibits platelet adhesionC) Binds to and inhibits Factor Xa and thrombinD) Blocks protease activity for Factor VIIaE) Forms a complex with thrombin

What initiates the process of fibrinolysis?A) Conversion of prothrombin to thrombinB) Activation of Factor XIIC) Conversion of plasminogen to plasminD) Formation of the tenase complexE) Activation of Factor V

Which factor, along with HMWK, cleaves Factor XI into Factor XIa?A) Factor IXaB) Factor XIIaC) Factor VIIIaD) Factor XaE) Factor Va

What triggers the intrinsic pathway of coagulation?A) Trauma to the vascular wallB) Contact with negatively charged surfacesC) Release of Tissue Factor IIID) Activation of Factor VIIE) Formation of a prothrombin activator

Which anticoagulant is used for bypass surgery and pulmonary embolism due to its short-acting nature?A) ProstacyclinB) Nitric oxideC) HeparinD) Antithrombin IIIE) Thrombomodulin

What is the role of the prothrombin activator in the coagulation process?A) To activate Factor XIIB) To convert prothrombin into thrombinC) To form a fibrin clotD) To release Tissue Factor IIIE) To inhibit thrombin formation

Which complex is responsible for activating Factor X in the intrinsic pathway?A) VIIa-Tissue Factor-Ca²⁺ complexB) IXa-VIIIa-Ca²⁺-Phospholipid complexC) Xa-Va-Phospholipid complexD) XIIa-HMWK complexE) Prothrombin activator complex

Which pathway is initiated by tissue injury and the release of tissue factor (factor III)?A) Intrinsic pathwayB) Extrinsic pathwayC) Common pathwayD) Fibrinolytic pathwayE) Platelet pathway

What is the main purpose of the common pathway in coagulation?A) To form the tenase complexB) To convert fibrinogen into fibrinC) To form the prothrombin activatorD) To activate Factor XIIE) To degrade the clot

What happens when Factor XII comes into contact with collagen or other negatively charged surfaces?A) It forms a fibrin clotB) It releases Tissue Factor IIIC) It undergoes a molecular configuration change and activatesD) It inhibits thrombin formationE) It converts prothrombin into thrombin

Which factor is responsible for converting fibrinogen into fibrin?A) Factor IXaB) Factor XaC) ThrombinD) TF/Factor VIIa complexE) Factor XIII

What initiates the extrinsic pathway of coagulation?A) Contact with negatively charged surfacesB) Trauma to the vascular wallC) Activation of Factor XIID) Release of Factor VIIIE) Formation of a fibrin clot

What is the role of factor XIII in the common pathway?A) Activates factor XB) Converts fibrinogen to fibrinC) Stabilizes fibrin strandsD) Activates factor IXE) Inhibits thrombin