Hemostasis

What is the SECOND step in the three phases of haemostasis?

• vascular phase

• intrinsic pathway

• extrinsic pathway

• platelet phase

Which of the following statements about platelets is INCORRECT?

• Platelets adhere to collagen fibers of damaged tissue

• Platelets are cell fragments of megakaryocytes

• Platelets activate the clotting cascade

• Platelets are involved in clot dissolution

In haemostasis, which molecule polymerises to become the insoluble blood clot?

• factor X

• thrombin

• fibrin

• plasmin

What is the first factor formed as a result of the extrinsic and intrinsic pathways of clot formation?

• fibrin

• thrombin

• factor X

• factor XIII

Which enzyme converts fibrinogen to fibrin?

• serotonin

• thrombin

• factor X

• factor XIII

Which of the following describes the role of factor X in blood clotting?

• to form a plug in the hole of the damaged blood vessel

• to convert prothrombin to thrombin

• to activate clotting factor V

• to release platelet factor 3

Which statement below about role of vitamin K in blood clotting is true?

• It helps in activation of all clotting factors

• It dissolves fibrin meshwork

• It is an antagonist of warfarin

• It activates anti-thrombin III

Hemophilia B is a disease caused by a deficiency of which clotting factor?

• Factor II

• Factor V

• Factor VIII

• Factor IX

Which of the following is the effect of von Willebrand disease?

• Prolonged bleeding time

• Prolonged clotting time

What is the main mechanism of action of heparin in blood clotting?

• Inhibits factor XIII

• Increases activity of anti-thrombin III

• Dissolves fibrin

• Promotes clot retraction