atheroma and infarction Flashcards
(15 cards)
What is an atheroma?
Accumulation of fatty acid deposits and scar tissue leading to restriction of circulation
What is an infarction?
Obstruction of blood supply, leading to death of tissue
How do cells take up fats from lipoproteins?
Receptor mediated endocytosis
Common sites of atheroma
- Carotid arteries & circle of Willis
- Coronary arteries
- Iliac arteries
- Aorta
Formation of atheroma?
- Free radicals cause oxidation of LDL cholesterol
- Oxidised LDL accumulates at site of damage at blood vessel
- Immune response sends macrophages to destroy it
- Macrophages digest LDL and digest it to small lipids
- Macrophages forms foam cell
- Foam cell releases chemical messengers to attract more macrophages
- Foam cell build up causes plaque
What can cause endothelial damage?
- hyptertension
- smoking
- hyperglycemia
- hypercholesterolemia
How do LDLs pass through endothelial cells?
Trancytosis
How do plaques form??
Write answer down
- Endothelial cells damage
- Increases permeability of arterial wall - allows LDLs to enter tunica intima
- Damaged endothelial cells express adhesion protein molecules, binds to white blood cells
- WBCs enter tunica intima via diapedesis
- WBCs produce free radicals, oxidising LDLs
- Oxidised LDLs attract more WBCs
- Positive feedback loop
- Macrophages engulf LDLs creating foam cells
- Accumulating lipid creates lipid core
- Endothelial cell cover plaque
- Plaque accumulates calcium salts
What happens if the central core is too large?
Plaque can rupture
Sub-endothelium exposed - procoagulant surface
thrombus formation
What can impact atheroma formation?
- Wood fire smoke - not significant but still a contributing factor
- Parasite infections lead to chronic inflammation - immune systems became more hyperactive compared to other organisms caused by parasitic infection such as malaria
- Genetic & environment influences - genetics play in vulnerability of the formation of atheroma’s
Where do venous occlusions occur
LEGS
occlusion here doesn’t cut off blood suply
causes pain and swelling
hyraulic pressure causes oedema
Arterial occlusions fav locations?
cardiac + carotid arteries
anything downstream from occlusion becomes O2 starved
Types of stroke?
Ischaemic
Haemorrhagic
Ischaemic stroke?
Due to thromboembolism
- Thrombus at carotid plaque rupture travels into smaller cerebral vessels.
- 85% from carotid atheroma rupture, 15% from stasis in left atrium due to arrhythmia.
Haemorrhagic stroke?
Due to hypoperfusion, loss of blood pressure (eg. heart failure, haemorrhage, shock), or aneurysm rupture and bleeding in the brain
