Thrombosis Flashcards
Function of platelets
- Secretion of pro-thrombotic substances
* Aggregation to form platelet plug
Platelet activating factors
- Exposed collagen
* Thrombin
Coagulation cascade activating factors
- Abnormal surfaces
* Tissue factor
Function of coagulation cascade
- Thrombin production
* Fibrin production
What is mainly involved in dissolving a clot?
Plasmin –> enzyme that breaks down fibrin into soluble ‘fibrin-degradation products’
Definition of thrombus
Blood clot forming in vessels of a living body
Definition of thrombosis
Process of thrombus formation
What is Virchow’s triad?
Summary of factors that predispose to thrombosis
Components of Virchow’s triad
- Alterations to blood flow
- Alterations to vessel wall
- Alterations to blood coagulability
What blood flow alterations predispose to thrombosis and why?
- Turbulence –> damages endothelium
* stagnation –> promotes clotting cascade activation
What are the vessel wall alterations the predispose to thrombosis?
- Anything affecting endothelial function
- Anatomical abnormalities that induce turbulent flow
- Loss of endothelium with collagen exposure
What causes hyper-coagulability (increased tendency for blood to clot)
- Increased viscosity
* Abnormalities in factors involved in thrombosis/thrombolysis
Consequences of thrombosis
- Fibrinolysis (thrombus broken down, healing by resolution)
- Fibrosis (scar formation over thrombus causing occlusion or stenosis or minimal blockage)
- Embolism
Definition of embolus
Object carried through circulation to point distant from origin
Substances that can embolise
- Thrombus
- Atheromatus debris
- Gas (nitrogen, air)
- Fat
