L6 Atherosclerosis, thrombosis, embolism, ischaemia, infarction Flashcards
What is a white infarction
death of a tissue as a result of ischaemia, looks pale with red border, in tissues supplied by arteries
What is a red infarction
congestion which leads to increased pressure and rupture of small vessels in an area of dual blood supply, venous occlusion
What is an infarction
acute ischaemic necrosis, mostly caused by thrombosis or embolism
Properties of endothelium (5)
barrier normally anti-thrombotic (prostacyclin + nitric oxide inhibit platelet aggregation) can be pro-thrombotic secrete vasodilators and constrictors normally resistant to leukocyte adhesion
What are platelets activated by
exposed collagen following vessel injury
What is a thrombus
clotted mass which doesn’t move from site of origin
What is thrombosis
formation of thrombus involving vessel walls, platelets and plasma proteins
What does Virchows triad involve
Stasis, hypercoagulability, damage to endothelium
What does stasis involve
plays important role in venous and arterial thrombosis
turbulence (aneurysm, atherosclerotic plaque)
slowing (post surgical, elderly, varicose veins, cardiac failure)
What factors increase coagulation
post operative, increased oestrogen, sepsis, obesity, dehydration
How can injury to the endothelium occur
smoking, direct trauma, infection, atherosclerosis, inflammation
What are arterial thrombi mostly caused by
atherosclerosis (endothelial injury) or aneurysm (turbulence)
What are venous thrombi mostly caused by
slowing of blood flow, deep leg and pelvic veins important
Examples of thrombi fate
embolization, fibrinolysis, organization, persistence (eg. aortic aneurysms)
What is an embolus
intravascular solid, liquid or gas carried in the blood stream to a remote site away from its origin
What are the risk factors for deep vein thrombosis
THE TRIAD
What is a pulmonary embolism
thrombi from deep VEINS of lower limbs embolise to the lungs
What is the path of a pulmonary embolism
veins to inferior vena cava to RA to RV to pulmonary arteries in lungs then STOPS (IT CANNOT CAUSE A STROKE)
What are the symptoms of a pulmonary embolism
most are asymptomatic, medium size = coughing up blood, large = sudden cardiac collapse
What is the consequence of a large pulmonary embolism
death (right heart ventricle failure)
What is atherosclerosis and what can it cause
formation of plaques on artery walls, chronic accumulation of lipids in intima of large and medium sized arteries
underlying cause of most heart attacks and stroke
What do plaques consist of
cholesterol core, fibrous cap
What are the risk factors of atherosclerosis
smoking, hypertension, increased age, being male, diabetes
Five step pathogenesis of atherosclerosis
- chronic endothelial injury
- endothelial dysfunction
- smooth muscle emigration and macrophage activation
- macrophages and smooth muscle cells engulf lipid
- smooth muscle cells proliferate