Atheroma, Thrombosis & Infarction Flashcards
Define atherosclerosis (3)
Accumulation of lipid, macrophages and SM cells in intimal plaques in (large & medium sized) epicardial coronary arteries, causing them to harden
What’s in a plaque? (4)
Lipid Necrotic core Connective tissue Fibrous cap Calcium, SM cells, Lymphocytes
What triggers atherosclerosis?
Endothelial damage
Give examples of agents that cause endothelial damage (3)
Physical stress - eg at bifurcations
Chemical irritants
Oxygen free radicals
Clinical risk factors for atherosclerosis (2)
Hypertension
Diabetes
Describe the progression to atherosclerosis
- Damage to endothelium - lipid & macrophages can enter
- Macrophages eat lipid, forming foam cells
- Formation of fatty streak
- Fibrous cap & necrotic core formation
- Plaque rupture - exposing underlying thrombogenic foam cells
- Blood clot can form, further occluding artery
How can atherosclerosis cause arteries to stiffen?
Ca deposited by SM cells
Define thrombus
Solid mass of blood constituents formed w/in intact vascular system during life
What 3 factors can cause thrombosis? (Virchow’s triad)
- Change in vessel wall eg endothelial damage
- Change in blood flow eg HT: laminar to turbulent flow
- Change in blood constituents eg raised cholesterol
What can thrombus transform into? (4)
Lysis + resolution
Organisation
Recanalisation (re-establishing flow)
Embolism –> embolus –>infarct
Define embolus
Mass of material in the vascular system able to lodge w/in vessels and block the lumen
What are some types of emboli?
Thromboemboli
Gas emboli
Fat emboli
Define ischaemia
Reversible damage to tissues, due to reduction in blood flow
Define infarction
Irreversible death of cells due to reduction in blood flow (ischaemia)
What is reperfusion injury? (3)
Return of blood flow and thus oxygen can activate oxygen-dependent free radical systems
Macrophages & neutrophil polymorphs clear away debris
Results in more tissue damage
