Thrombosis 2

Question 1

Haemostatic balance is the balance between ______ and _______

Answer 1

Pro-coagulant proteins + anti-coagulant proteins

Question 2

What are the 6 steps in haemostasis?

Answer 2

1. Vessel injury
2. Endothelium vasoconstricts
3. Platelets adhere –> platele plug forms
4. Clotting cascade initiated –> fibrin clot forms
5. Antithrombotic proteins inactivate
   clotting proteins to stop the clot from continuing to expand
6. Fibrin clot removed by fibrinolytic enzymes (plasmin)

Question 3

Clotting factors assemble on cell membranes to form which 3 PRO-COAGULANT COMPLEXES?

Answer 3

1. Extrinsic X-ase complex
drives (by IX)
2. Intrinsic X-ase complex
drives (by X)
3. Prothrombinase complex: fibrinogen to fibrin

*** Note: Extrinsic X-ase complex also drives Prothrombinase complex (by X)

Question 4

Thrombin converts _____ to _____ (stable clot)

Answer 4

fibrinogen, fibrin

Question 5

Name 3 circulating clotting inhibitors and what they inhibit.

Answer 5

1. Antithrombin - thrombin
2. Tissue factor pathway inhibitor - tissue factor
3. Protein C + Protein S - co-factors 8a (found on intrinsic Xase complex) and 5a (found on prothrombinase complex)

Question 6

______ is the main protease responsible for the degradation of fibrin (to get rid of the clot)? Degrades fibrin —> fibrin degradation products.
This process is known as FIBRINOLYSIS.

Answer 6

Plasmin

Question 7

What happens if a person has a Factor V Leiden + prothrombin gene mutation?

Answer 7

Activity of factors 5 and 2 are increased in the prothrombinase complex resulting in too much fibrinogen being converted to fibrin.

Question 8

What does PROTHROMBIN TIME (PT) measure?

What is the normal range?

Answer 8

Extrinsice X-ase Complex

normal range 12.3 - 14.5 sec

Question 9

What does ACTIVATED PARTIAL THROMBOPLASTIN TIME (APTT) measure?
What is the normal range?

Answer 9

Intrinsic X-ase Complex

normal range 24 - 34 sec

Question 10

2 disorders of haemostasis causing bleeding are:
Inadequate number of OR dysfunctional ______
Inadequate number of OR dysfunctional ______

Answer 10

Platelets

Coagulation Factors

Question 11

5 disorders of haemostasis causing thrombosis are:

Answer 11

1. Factor 5 Leiden
2. Prothrombin gene mutation
3. Antithrombin deficiency
4. Protein C + S deficiency
5. Hormonal changes - pregnancy, the pill