Hemostasis, thrombosis, embolism Flashcards
what are 4 steps in hemostasis at site of vascular injury
- vasocontriction
- primary hemostasis
- secondary hemostasis
- counterregulatory mechanism
Name 3 things that happen in primary hemostasis
platelet adhesion
platelet activation
platelet aggregation
what happens in platelet adhesion
platelets adhere ECM with help of von Willebrand factor
what happens in platelet activation
platelets change shape
release secretory granules (recruit more platelets)
what happens in platelet aggregation
hemostatic plug
name 3 main things in secondary hemostasis
tissue factor
thrombin
cross-linked fibrin
tissue factor? when is it released and what does it activate
released at site of injury
activates coagulation cascade
2 role of thrombin
convert fibrinogen to insolube fibrin
- further platelet recruitment
cross-linked fibrin does what
permanent plug, prevents further hemorrhage
how does adhesion between platelets occur
von Willebrand factor bridges platelet surface receptor glycoprotein IB and collagen
name 2 categories of granules that bind to platelets for activation
alpha
gamma
what appears on platelets to allow for activation and what does it bind to
phospholipid
Calcium
role of ADP and thromboxane A2
amplify aggregation forming hemostatic plug
what does thrombin bind
protease-activated receptor (PAR) on platelet membrane
at what point is platelet aggregation reversible
thrombin binding
before platelet contraction
