Process of stopping bleeding, keep blood within the damaged vessel.
1 of 15
What are the three main steps in haemostasis?
vasoconstriction, formation of platelet plug and blood coagulation.
2 of 15
What are the two types of plug?
a temporary haemostatic plug and a definitive haemostatic plug.
3 of 15
How are platelets activated?
Activated by the release of contents of intracellular granules.
4 of 15
What does serotonin do?
Is a vasoconstrictor, activates and aggregates platelets.
5 of 15
What does the platelet activating factor do?
Converts membrane phospholipids to thromboxane A2. Is a vasoconstrictor. It increases capillary permeability causing inflammation.
6 of 15
Where is the Von Willebrand factor stored?
Weibel-palade bodies
7 of 15
How is the formation of a platelet plug stopped?
Nitric oxide and PGL2 (prostacyclin) released from endothelium when it repairs, degrades the platelet plug.
8 of 15
What are zymogens?
inactive enzymes.
9 of 15
Discuss thrombomodulin
Endothelial surface receptor protein, Binds thrombin, Complex activates protein C, which complexes with protein S and inactivates factor Va and factor VIIIa
10 of 15
Discuss antithrombin III
Plasma protein (from liver), Binds to heparin on endothelial surface, Blocks factors IX, X, X1, XII, Thrombin, Kallikrein, Facilitated by heparin
11 of 15
What is fibrinolysis?
This is clot dissolution, is a temporary process.Uses plasminogen which is cleaved to plasmin. tPA is secreted by the endothelium and is activated by fibrin, it is the tPA that carrys out the cleavage.
12 of 15
What is thrombosis?
can stop blood formation and clotting can occur within intact vessels. It is activated by atheroma. This leads to embolism.
Comments
No comments have yet been made