Atherosclerosis Flashcards
(22 cards)
What is Atherosclerosis?
Hardening of the arteries (disease)
Which arteries are affected by atherosclerosis? (size)
Medium to large only
What is an Atheroma?
Fibro-fatty plaque which has 2 main parts:
• A lipid rich central core
• Intimal fibrous cap
What complications arise from Atherosclerosis?
Other health conditions
- Myocardial infarction
- Aneurysms
- Peripheral vascular disease
What are the risk factors for Atherosclerosis?
- Age
- Sex (oestrogen protects against it but after menopause pretty much equal
- Hyperlipidaemia
- Hypertension (above 140 systolic)
- Smoking
- Diabetes mellitus
What can cause chronic endothelial injury?
- haemodynamic disturbances
- Smoking
- Toxins
- Hypercholesterolemia
- Hypertension
- Viruses
- Immune reactions
Describe the steps of the formation of an atheroma
- Chronic endothelial injury
- Endothelial dysfunction: increased endothelial permeability, increased leukocyte adhesion, increased monocyte adhesion and migration
- Smooth muscle emigration from the media to intima, macrophage activation
- Macrophages and smooth muscle cells engulf lipids
- Smooth muscle proliferation, collagen and other ECM deposition, extracellular lipid
What is the role of lipids in atherosclerosis?
- Hyperlipidaemia (LDL cholesterol)
- Impairs endothelial function (more permeable)
- Accumulates within the intima (cholesterol)
- Causes the oxidative modification of LDL
What happens after LDL has gone through oxidative modification? (Regarding lipids and macrophages)
- They are ingested by macrophages via SCAVANGER receptors and form foam cells
- This is chemotactic for monocytes
- Inhibits the motility of macrophages
- Stimulates the release of cytokines
- It is cytotoxic to endothelial and smooth muscle cells
- Eventually die
What is secreted by foam cells?
- Interleukin 1 (IL1)
- Tumor necrosis factor (TNF)
- Monocyte chemotactic protein 1)
- Growth factors
What is a fatty streak?
Accumulation of phagocytes, macrophages, cholesterol
Slight raise in the lumen of blood vessels
What does a fatty streak develop into?
A mature fibro-fatty Atheroma
What happens to smooth muscle after it starts to migrate?
- Migrates from media to intima
- Some die
- Some cells change into collagen
Describe an atheromatous plaque
- Fibro-fatty plaque
- Patchy and raised white to yellow 0.3-1.5cm
- lipid core
- Fibrous cap
What forms the fibrous cap of an atheromatous plaque?
- Smooth muscle cells
- Macrophages
- foam cells
- Lymphocytes
- collagen
- Elastin
- Proteoglycans
What forms the necrotic centre of the atheromatous plaque?
- Cell debris
- Cholesterol crysals
- Calcium
- Foam cells
In order from most to less likely, where are the 6 most common places for atherosclerosis to be found?
- Abdominal aorta
- Coronary arteries
- Popliteal arteries
- Descending thoracic aorta
- Internal carotid arteries
- Vessels of the circle of willis (Brain)
What are the complicated lesions regarding atherosclerosis?
- Calcification
- Rupture or ulceration
- Haemorrhage
- Thrombosis
- Aneurysmal dilation
Describe the morphology of fatty streaks
- Starts as a fatty dot (less than 1mm)
- Become elongated streaks (1cm or longer)
- Form from foam cells and T lymphocytes
- Present in the aorta from less than 1 year
- present in coronary artery in adolescence
- May be precursors of plaques
When will there be clinical features of atherosclerosis and what are they?
Only if there are complications: • Thrombosis • Calcification • Aneurysmal dilation • Ischaemic events: - Heart - Brain - Lower extremities - Other organs
What are the primary preventions of atherosclerosis?
- Stop smoking
- Control hypertension
- Weight reduction
- Lowering total LDL
- Reduce calorie intake
What are the secondary preventions of atherosclerosis?
- Prevent complications
- Anti-platelet drugs in thrombosis
- Lower blood lipid levels
