Haemostasis Flashcards
1
Q
in general, what happens in response to injury?
A
- vessel constriction
- formation of an unstable platelet plug (platelet adhesion, platelet aggregation)
- stabilization of plus with fibrin (blood coagulation)
- dissolution of clot and vessel repair
2
Q
what happens when the cell line breaks?
A
- tissue factors can pour into lumen
- bring about haemostasis
3
Q
what are functions of the endothelium?
A
- maintain barrier between blood and TF
- synthesis: PGI2, thrombomodulin, vWF, plasminogen activators
4
Q
describe the steps to platelet creation
A
- stem cell precursors
- megakaryocytes
- megakaryocytes mature and granulate
- megakaryocytes produce around 4000 platelets
5
Q
what is the lifespan of a platelet. where are they stored?
A
- lifespan around 10 days
- 1/3 stored in spleen
6
Q
what binds to GIp1b?
A
vWF
7
Q
what binds to GIp1a?
A
collagen
8
Q
how do the platelets become partially activated?
A
- by release of ADP and thromboxane from other platelets
- causes platelets to express G1p2b/3a receptors for enhances aggregation
9
Q
how does thrombin get involved?
A
thrombin can amplify the response from its own pathway by partially activating the platelets directly
10
Q
what is the difference between prostaglandin and enothelial cells in prostaglandin metabolism?
A
- endothelial cells create PGI2
- platelets produce TXA2
- pathways the same but enzymes found inside cells differ
- endothelial cell = prostacyclin synthetase
- platelets = thromboxane synthestase
