Atherosclerosis Flashcards
Where does atherosclerosis effect?
Medium to large muscular arteries
What is an atheroma composed of?
An intimal fibrous cap and a central core rich in lipids
What is the clinical significance of atherosclerosis
It contributes to half of all deaths in the western world
What are the risk factors for atherosclerosis
Age, Sex, Genetics, Hyperlipidaemia Hypertension Smocking Diabetes Mellitus
What are the three stages of atherosclerosis
Initiation formation stage - precursors
Adaptation stage - formation of atheroma
Clinical stage - complications
Name the pathogenesis that contribute to atherosclerosis
- Chronic endothelial injury/dysfunction
- Role of lipids
- Role of macrophages
- Smooth muscle proliferation
- Formation of a fibro-lipid plaque
- Injury to the plaque - thrombus formation
How can endothelial become damaged?
Because of; Haemodynamic disturbances, Hypercholesterolemia Hypertension Smoking Toxins Viruses Immune reactions
What happens with chronic endothelial injury?
Increased endothelial permeability,
Increased leukocyte adhesion and,
Increase monocyte adhesion and migration from lumen to tunica intima.
What occurs when monocytes migrate into the tunica intima
They can now be called macrophages
Describe the role of lipids in the development of atherosclerosis
Hyperlipidaemia (LDL cholesterol) leads to impaired endothelial function, accumulates within the tunica intima and causes the oxidative modification of LDL
Describe the role of macrophages in the development of atherosclerosis
They can engulf oxidised LDL and therefore become foam cells. The foam cells then secrete granules that recruit more macrophages to the tunica intima. Eventually the accumulation of foam cells leads to the development of fatty streaks (areas where the tunica intima is raised)
Foam cells are immobile so die in the tunica intima, the cholesterol within them becomes crystallised.
Describe the role of smooth muscle proliferation in the development of atherosclerosis
Smooth muscle cells migrate from the tunica media to the tunica intima where they begin to move to the surface of the plaque. Here they deposit collage and extracellular matrix which leads to the development of the mature fibro-fatty atheroma.
What does an atheroma look like?
A raised, yellow patch of tissue that can be 0.3-1.5cm. It has a core of lipid and a fibrous cap (collagen, elastin etc).
Where are the most common places for atheroma’s to develop?
From most common to least common; Abdominal aorta, coronary arteries, popliteal arteries, descending thoracic aorta internal carotid arteries vessels from the circle of Willis (in the brain)
What complications arise from atheroma’s?
Calcification, rupture or ulceration, haemorrhage, thrombosis, aneurysmal dilation and ischaemic events. (will only know of a atheroma if you then get complications)
