Haemostasis Flashcards
What prevents blood cells from sticking to the vessel wall?
- Nitrous oxide
- Thrombin
- Heparins
- TFPI
- Prostacyclin
What happens when you cut yourself and the vessel is damaged?
resting platelets and resting coagulation factors become activated
What is responsible for clot formation?
Platelets
vWF
coagulation factors
What is responsible for keeping clot to the site of injury?
Natural anticoagulants
What is responsible for the clot disappearing?
Fibrinolytic system
What are the roles of the platelets in haemostasis?
- adhere- to the abnormal surface
- activation- through a variety of pathways
- aggregation- to form a clot/ platelet plug
What do platelets provide?
phospholipid surface for coagulation
What do platelets bind to?
- Collagen via glycoprotein 1a
* vWF via glycoprotein 1b
How are platelets activated?
- ADP- P2y12
* COX pathway
What is the function of ADP- P2y12?
prevent platelet becoming sticky and clotty
What is the function of COX pathway?
Arachidonic acid converted into Thromboxane A2 via COX
What causes the aggregation of platelets?
- Thromboxane (main)
* Scramblase
What does von Willebrand factor bind to?
Factor 8 (factor 8 important for making a clot)
The surface of platelets via glycoprotein 1b
The collagen surface via a few receptor sites
Glycoprotein 23ba
What is the primary haemostatic plug?
Platelet plug
What is the secondary haemostatic plug?
Fibrinogen, on the platelets, is cleaved by thrombin forming a fibrin plug
