10. Atherosclerosis Flashcards
(21 cards)
What is the definition of atherosclerosis?
Accumulation of intracellular and extracellular lipid in intima and media of large and medium sized arteries
Thickening and hardening of arterial walls
What is the fatty streak in atherosclerosis?
Lipid deposits in intima
Yellow, slightly raised
What is the simple plaque in atherosclerosis?
Raised yellow/white
Irregular outline
Widely distributed
Enlarge and coalesce
What is complicated plaque in atherosclerosis?
Thrombosis
Haemorrhage into plaque
Calcification
Aneurysm formation
What are the common sites for atherosclerosis?
Aorta Coronary arteries Carotid arteries Cerebral arteries Leg arteries
What are the early changes in microscopic features of atherosclerosis?
- proliferation of smooth muscle cells
- accumulation of foam cells
- extracellular lipid
What are the later changes in microscopic features of atherosclerosis?
Fibrosis Necrosis Cholesterol clefts \+/- inflammatory cells Disruption of internal elastic lamina Damage extends into media In growth of blood vessels Plaque fissuring
What are the clinical effects of atherosclerosis?
Ischaemic heart disease: - sudden death - MI - angina pectoris - arrhythmias - cardiac failure Cerebral ischaemia: - transient ischaemic attack - stroke - multi-infarct dementia Mesenteric ischaemia: - colitis - malabsorption - intestinal infarction Peripheral vascular disease -gangrene - claudication
What are the risk factors for atherosclerosis?
Age Gender Hyperlipidaemia Smoking Hypertension Diabetes mellitus Alcohol Infection
What are the infections that can cause atherosclerosis?
Chlamydia pneumoniae
Helicobacter pylori
Cytomegalovirus
What are some less important risk factors?
Lack of exercise
Obesity
Soft water
Oral contraceptives
What are the processes involved in atherosclerosis?
Thrombosis
Lipid accumulation
Production of intercellular matrix
Interaction between cell types
What are the cells involved in atherosclerosis?
Endothelial cells Platelets Smooth muscle cells Macrophages Lymphocytes Neutrophils
How are endothelial cells involved in atherosclerosis?
Key role in haemostasis
Altered permeability to lipoproteins
Production of collagen
Stimulation of proliferation and migration of smooth muscle cells
How are platelets involved in atherosclerosis?
Key role in haemostasis
Stimulate proliferation and migration of smooth muscle cells
How are smooth muscle cells involved in atherosclerosis?
Take up LDL and other lipid to become foam cells
Synthesise collagen and proteoglycans
How are macrophages involved in atherosclerosis?
Oxidise LDL
Take up lipids to become foam cells
Secrete proteases which modify matrix
Stimulate proliferation and migration of smooth muscle cells
How are lymphocytes involved in atherosclerosis?
TNF may affect lipoprotein metabolism
Stimulate proliferation and migration of smooth muscle cells
How are neutrophils involved in atherosclerosis?
Secrete proteases leading to continued local damage and inflammation
How can you help prevent atherosclerosis?
No smoking Reduce fat intake Treat hypertension Not too much alcohol Regular exercise/weight control
What are the interventions for atherosclerosis?
Stop smoking Modify diet Treat hypertension Treat diabetes Lipid lowering drugs
