Haemostasis

Question 1

What substance binds platelets to each other in a primary haemostatic plug?

Answer 1

Fibrinogen

Question 2

What substance starts the coagulation cascade?

Answer 2

Tissue Factor

Question 3

What converts fibrinogen to fibrin to form a secondary haemostatic plug?

Answer 3

Thrombin

Question 4

Which three substances are released by the platelet granules during platelet aggregation?

Answer 4

TXA2
ADP
5-HT

Question 5

How does the thrombolytic cascade start?

Answer 5

Thrombin promotes production of Antithrombin and conversion of Plasminogen to Plasmin

Question 6

What does Plasmin do?

Answer 6

Breaks apart Fibrin struts

Question 7

What is the order of the Extrinsic pathway?

Answer 7

TF -> VII -> X

Question 8

What is the order of the Intrinsic Pathway?

Answer 8

XII -> XI -> IX + VIII -> X + V

Question 9

How does Aspirin affect clot formation?

Answer 9

Prevents release of TXA2 (prostaglandin)

Question 10

How does Clopidogrel affect clot formation?

Answer 10

Prevents release of ADP

Question 11

How does Abciximab affect clot formation?

Answer 11

Competitively binds the GP IIb/IIIa receptor, preventing binding of fibrinogen

Question 12

How does Alteplase affect clot formation?

Answer 12

tPA analogue, causing formation of Plasmin from Plasminogen, and thereby breaking the Fibrin Mesh

Question 13

What causes platelets to stick to a breach in the endothelium?

Answer 13

Exposed collagen fibres and Von Willebrand Factor (vWF)