22 Questions
What is the result of endothelial cell injury and dysfunction in atherosclerosis?
Increased vascular permeability
What is the composition of fatty streaks in atherosclerosis?
Lipid-filled foamy macrophages
What is the role of PDGF in atherosclerosis?
Induce smooth muscle cell recruitment and proliferation
What is a complication of atherosclerosis?
All of the above
What is a characteristic of atherosclerotic plaques?
Composed of lipid-filled macrophages and extracellular matrix
What is a risk factor for atherosclerosis?
All of the above
What is the critical percentage of luminal cross-sectional area decrease that typically occurs in atherosclerotic stenosis?
70%
Which cell type is a component of atherosclerotic plaques?
T cells
What is the consequence of atherosclerotic plaque rupture?
Atheroembolism
What is the main component of the extracellular matrix in atherosclerotic plaques?
Collagen
What is the term for the formation of a new blood vessel within an atherosclerotic plaque?
Neovascularization
What is the term for the accumulation of lipids within atherosclerotic plaques?
Atheroma
What is the consequence of atherosclerosis-induced pressure or ischemic atrophy of the underlying media?
Aneurysm formation
What is the term for the narrowing of the vessel lumen due to atherosclerotic plaques?
Atherosclerotic stenosis
What is the term used to describe the hardening of the arteries?
Arteriosclerosis
What is the characteristic of atherosclerotic plaques?
A soft core of lipid covered by a fibrous cap
What is the result of the rupture of an atherosclerotic plaque?
Obstructive thrombosis
What is the underlying condition of coronary, cerebral, and peripheral vascular disease?
Atherosclerosis
What is the result of atherosclerotic plaques enlarging?
Stenosis
What is the consequence of atherosclerotic plaques increasing the diffusion distance from the lumen to the media?
Ischemic injury and weakening of the vessel wall
What is the term used to describe the lesions that impinge on the vascular lumen and can rupture to cause sudden occlusion?
Atheromas
What is the location of the arteries affected by atherosclerosis?
Medium-sized to large arteries
Study Notes
Atherosclerosis
- Atherosclerotic plaques have three components: cells (smooth muscle cells, macrophages, and T cells), extracellular matrix (including collagen), and intracellular and extracellular lipid.
- Atherosclerotic plaques can gradually occlude vessel lumina, compromising blood flow and causing ischemic injury.
Morphology
- Atherosclerotic plaques consist of a central lipid core, a fibrous cap, and a residual lumen.
- Inflammation, calcifications, and neovascularization are common features of atherosclerotic plaques.
Atherosclerosis Consequences
- Atherosclerotic stenosis: narrowing of the lumen, causing ischemic injury, typically occurs when the occlusion produces a 70% decrease in luminal cross-sectional area.
- Rupture, ulceration, and erosions: exposing highly thrombogenic plaque constituents (collagen), which can lead to hemorrhage, atheroembolism, and aneurysm formation.
- Atheroembolism: plaque rupture can discharge atherosclerotic debris into the bloodstream, producing microemboli that can block distant arteries.
- Aneurysm formation: atherosclerosis-induced pressure or ischemic atrophy of the underlying media, with loss of elastic tissue, causes weakness and potential rupture.
Pathogenesis
- Endothelial cell injury and dysfunction cause increased vascular permeability, leukocyte and platelet adhesion, and inflammation.
- Injured endothelial cells allow the accumulation of lipoproteins, leading to monocyte migration into the intima and transformation into macrophages and foam cells.
- Smooth muscle cells produce extracellular matrix (collagen) and inflammatory cytokines, which activate T-cells.
- PDGF (from activated platelets, macrophages, endothelial cells, and smooth muscle cells) induces smooth muscle cell recruitment and proliferation.
Morphology – Fatty Streaks
- Fatty streaks: composed of lipid-filled foamy macrophages, beginning as multiple minute flat yellow spots, eventually coalescing into elongated streaks 1 cm long or longer.
Arteriolosclerosis
- Arteriosclerosis: hardening of the arteries, a generic term reflecting arterial wall thickening and loss of elasticity, with distinct clinicopathologic conditions: atherosclerosis, arteriolosclerosis, and Mönckeberg medial sclerosis.
Atherosclerosis
- Characterized by intimal lesions called atheromas (or atheromatous or atherosclerotic plaques) that impinge on the vascular lumen and can rupture to cause sudden occlusion.
- Involves medium-sized to large arteries and underlies the pathogenesis of coronary, cerebral, and peripheral vascular disease.
This quiz covers the components and morphology of atherosclerotic plaques, including cells, extracellular matrix, and lipid. It also touches on ulceration and thrombus in complicated lesions.
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