Atherosclerosis Flashcards
What is atherosclerosis?
Formation of elevated lesions in tunica intima
What is arteriosclerosis?
Age related change in muscular arteries, thickening and hardening of the walls of arteries
What is the first stage of atherosclerosis?
Fatty streak - yellow linear elevation of intimal lining, consists of lipid-laden macrophages just below endothelium, may disappear, no significance, present in kids, may develop to atheromatous plaque
What is the second stage of atherosclerosis?
Early atheromatous plaque, go and develop to plaque, smooth yellow patches, central lipid core, lipid-laden macrophages
What is the third stage of atherosclerosis?
Fully developed atheromatous plaque, has central lipid core rich in lipids and debris from macrophages, fibrous cap, covered by endothelium, they are highly thrombogenic, can also have calcium depositions where necrotic tissue is present
What are foamy macrophages?
They can be present in fully developed plaque, can form a rim, due to oxidised lipoproteins uptake via special receptors
What are the common sites of plaque formation?
At bifurcation points, where there is turbulent flow
What is complicated atheroma?
established plaque with features such as haemorrhage, plaque rupture/fissuring or thrombosis
What is the biggest risk factor in atherosclerosis?
Hypercholesterolaemia, can be homo or heterozygous, lack of cell LDL receptor
What are other risk factors ?
smoking, hypertension, diabetes mellitus, male, elderly, less strong risk factors include obesity, sedentary lifestyle, low birth weight, low socio-economic status
What is the firth step in development of atheromatous plaque?
endothelial injury, can be caused by haemodynamic disturbance and turbulent flow, or hypercholesterolaemia that increases production of reactive oxygen species that modify the aggregated lipoproteins, then they are taken up by macrophages but they can’t be completely destroyed and format macrophages are formed, they are toxic to endothelium in addition to realising cytokines and growth factors, this is cyclic process
What is the second step in formation of atheromatous plaque?
functional alteration of endothelium by the injury, high permeability for `LDL, increased thrombogenicity, expression of cell adhesion molecules
What is the third step ?
Accumulation of lipoproteins LDL in the walls of blood vessels
What is the fourth stage?
Monocytes adhere to the endothelium, migrate to the intimal layer, phagocytosis and transformation to foamy macrophages
What is the fifth step?
Aggregation of platelets
