Session 6 - Atherosclerosis Flashcards
What is atheroma?
Accumulation of intracellular and extracellular lipid in the intima and media of large and medium sized arteries
What is atherosclerosis?
Thickening and hardening of arterial walls as a consequence of atheroma
What is arteriosclerosis?
Thickening of the walls of arteries and arterioles usually as a result of hypertension or diabetes mellitus
What are the 3 variable macroscopic appearances of atherosclerosis?
Fatty streak
Simple plaque
Complicated plaque
What is the fatty streak?
Lipid deposits in intima, yellow slightly raised
What is a simple plaque?
Raised yellow/white, irregular outline, widely distributed, enlarge and coalesce
What is the complicated plaque?
When there is thrombosis, haemorrhage into plaque, calcification, aneurysm formation
What are 5 common sites of atherosclerosis?
Heart Brain Kidneys Legs Bowels
What are the 6 layers of a normal arterial structure?
Endothelium Sub endothelial connective tissue Internal elastic lamina Muscular media External elastic lamina Adventitia
What are 3 microscopic features of the early stages of atherosclerosis?
Proliferation of smooth muscle cells
Accumulation of foam cells
Extracellular lipid
What are 8 microscopic features of atherosclerosis in later stages?
Fibrosis Necrosis Cholesterol clefts Inflammatory cells Disruption of internal elastic lamina Damage extends into media In growth of blood vessels Plaque fissuring
What are 5 cellular events that happen during plaque formation?
- Chronic endothelial insult causes endothelial dysfunction
- Lipid droplets and monocytes crosses endothelium and accumulate in intima, becomes oxidized and phagocytosed by macrophages = foam cells
- Crowded foam cells causes endothelium to bulge, smooth muscles cells migrate into lesion and proliferates, forming fatty streak
- Foam cells and SM a cells increase and plaque grows, fibrous cap forms with collagen and elastin, endothelium stretches over and gaps appear, which platelets adhere to
- Cells in centre of plaque dies and necrosis develops, dead cells release cholesterol so crystals appear in plaque, small blood vessels grow into plaque and it may undergo calcification
What are the 6 cells involved in formation of an atherosclerotic plaque?
Endothelial cells Platelets Smooth muscle cells Macrophages Lymphocytes Neutrophils
What is the role of endothelial cells in atherosclerosis?
Produce collagen
Stimulate proliferation and migration of smooth muscle cells
What is the role of platelets in atherosclerosis?
Stimulate proliferation and migrate of smooth muscle cells using platelet derived growth factor
What is the role of smooth muscle cells in atherosclerosis?
Take up LDL and other lipids to become foam cells, synthesise collagen and proteoglycans
What is the role of macrophages in atherosclerosis?
Oxidise LDL, take up lipids to become foam cells, secrete proteases which modify matrix, stimulate proliferation and migration of smooth muscle cells
What is the role of lymphocytes?
Stimulate proliferation and migration of smooth muscle cells
What is the role of neutrophils in atherosclerosis?
Secrete proteases leading to continued local damage and inflammation
What are 5 heart conditions that can occur due to atherosclerosis?
Myocardial infarction Chronic ischaemic heart disease Arrhythmias Cardiac failure Sudden cardiac death
What are 3 brains conditions that can occur due to atherosclerosis?
Transient ischaemic attacks
Cerebral infarction
Multi infarct dementia
What are 2 kidney conditions that can occur due to atherosclerosis?
Hypertension
Renal failure
What are 2 leg conditions that can occur due to atherosclerosis?
Peripheral vascular disease
Gangrene
What are 3 bowel disease that can occur due to atherosclerosis?
Ischaemic colitis
Malabsorption
Bowel infarction
