haemostasis, thrombosis and coagulation (L5) Flashcards
What is haemostasis
maintain fluid flow through the vasculature
What is thrombosis
pathological, causes restriction or blockage of a blood vessel
What are the three stages of haemostasis
- vascular spasm
- Platelet plug formation
- coagulation
What is vascular spasm
damaged blood vessels constrict reducing blood flow in the damaged area
What is primary haemostasis
platelet activation and plug formation
What is secondary haemostasis
coagulation
3 critical components of platelets
membrane proteins
secretory granules
surface-connected open cannalicular system
What is the most numerous platelet secretory granule
Alpha granules
What do alpha granules contain (4)
Adhesive proteins
platelet-specific proteins
membrane protein
alpha granule-specific proteins
3 adhesive proteins of alpha granules
fibroinogen
fibronectin
vWF
3 things dense granules contain
vasocontructive agents (serotonin) Platelet agonists (ADP, ATP) Calcium and magnesium
What complex is important for binding vWF
GP2b
What is von willebrand factor
blood glycoprotein
What receptor id for fibrinogen and platelet aggregation (and vWF interaction)
GP2a3B
When vessel damage occurs what is exposed
collagen-associated (vWF on collagen`)
What connection is made on the platelet with the exposed vWF
GP1b-vWF interactions
How does the platelet form a stronger adhesion with the sub-endothelium
rolling promotes more Gb1b/ vWF associations
What does a stronger adhesion of platelet with sub-endothelium cause
platelet activation –> granule release
Conformational change—> stronger adhesion molecules
What platelet agonist are released after platelet activation (3)
ADP,
thromboxane
Fibrinogen
What does fibrinogen cross bridges bind to
GP2a3b
What are zymogens
inactive precursors of enzymes
Coagulation factors are a group of____
Zymogens
What the two basic pathways for coagulation
extrinsic
intrisic
how is the extrinsic pathway triggered
by trauma