MOD 13 - Atherosclerosis and embolism Flashcards
definition of atherosclerosis
degeneration of arterial walls characterised by fibrosis, lipid deposition and inflammation which limit blood circulation and predisposes to thrombosis
what are the commonly affected arteries
bifurcations (sites of turbulent flow), abdominal aorta, coronary arteries, popliteal arteries, carotid vessels, circle of willis
risk factor for atherosclerosis
age, male, FH, genetics, hyperlipidaemia (LDL:HDL), hypertension, smoking, diabetes, CRP, stress
what is the first step in the road to atherosclerosis
endothelial injury (arises due to chronic injury and repair of the endothelium) - haemodyanmic injury , chemicals, immune complex deposition, irradiation
how is atheroma formed
- endothelial injury
- hyperlipidaemia (lipid deposit in intima by the recognition of scavenger receptors which recognise LDL)
- monocytes migrate into intima (lipid and endothelial injury) to ingest lipid forming ‘foam cell’ - fatty streak
- foam secrete chemokines
- attract more monocytes, lymphocyes & smooth muscle cells
- smooth muscle cells proliferate and secrete connective tissue
- mixture of fat, extracellular material and luekocytes and smooth muscle form the atherosclerotic plaque
what is the constituent of atherosclerotic plaque
fat, extracellular material, leukocytes, smooth muscle
what is atheromatous plaque
progression of atherosclerotic plaque
fibrous cap (smooth muscle cells, macrophages, foam cells, lymphocytes, collagen etc), necrotic center, media
what is the structure of the atheromatous plaque
shoulder, cap, core
what will happen to the atherosclerosis
grow larger, occlusion of the arteries, weakening of vessel walls (aneurysm formation), erosion (thrombosis)
what is thrombosis
solidification of blood content formed in the vessel during life
what are the difference between thrombosis and a clot
thrombus - within the body during life, dependent on platelets, firm
clot - stagnant blood, enzymatic process, elastic, adopts shape of vessels
what does the platelet adhesion and subsequent thrombous require according to virchow’s triad
intimal surface of the vessel, pattern of blood flow, blood constituents
how does arterial thrombus form
normal - atheroma (change in flow) - ulceration (loss of endothelial cells) - platelet adherence to the ulcerative site - thrombus formation
what can cause cardiac thrombosis
arrhythmias and cardiomyopathy
what is the sequelae of thrombosis
occlusion of vessel, resolution, incorporation into vessel wall, recanalisation, embolisation
