Blood clotting

Question 1

Haemostasis.

Answer 1

Maintenance of blood in clot free state in normal blood vessels, induces a rapid formation of a localized haemostatic plug at the site of vascular injury

Question 2

Thrombosis.

Answer 2

Pathological state of inappropriate activation of the normal haemostatic process.

Question 3

Embolus.

Answer 3

A clot that breaks loose and travels through the bloodstream.

Question 4

Venous thrombosis.

Answer 4

Protein rich, often occurs in the legs and lungs, PE and DVT.

Question 5

Venous thrombosis.

Answer 5

Protein rich, often occurs in the legs and lungs, PE and DVT.

Question 6

Arterial thrombosis.

Answer 6

Platelet rich, occurs in heart (MI), brain (stroke), peripheral vascular disease claudication.

Question 7

Function of tissue factor.

Answer 7

Released by damaged endothelial cells at site of injury, activates initial step in coagulation cascade (extrinsic pathway).

Question 8

Function of factor VII.

Answer 8

First step in extrinsic cascade.

Question 9

Function of factor X.

Answer 9

Final common pathway activation, conversion of prothrombin to thrombin.

Question 10

Function of thrombin.

Answer 10

Converts fibrinogen to fibrin.

Question 11

Function of fibrinogen.

Answer 11

Polymerisation to form a clot.

Question 12

Describe the endogenous regulation of coagulation.

Answer 12

Tissue factor pathway inhibitor (TFPI) always present in plasma that directly inactivates Xa, and produces feedback inhibition of VIIa/TF catalytic complex.