Atherosclerosis Revision Sheet

1. 📌 Essentials

• A disease characterized by lipid deposits (atheromas) in medium-large arteries' intima.
• Main risk factors: hypercholesterolemia, hypertension, smoking, diabetes, age.
• Initiates with endothelial dysfunction precipitated by risk factors.
• LDL cholesterol infiltration and oxidation trigger early lesion development.
• Foam cells derive from monocytes that migrate and transform in the vessel wall.
• Plaques consist of a lipid core, fibrous cap, and cellular components.
• Plaque stability depends on collagen content and lipid richness.
• Cap rupture leads to thrombus formation, causing ischemia or infarction.
• Symptoms are often asymptomatic until >70% arterial narrowing.
• Affected arteries: coronary, carotid, lower limb arteries.

2. 🧩 Key Structures & Components

• Endothelial cells — regulate vascular permeability; initial site of dysfunction.
• LDL cholesterol — deposits in arterial wall, oxidizes contributing to atherogenesis.
• Monocytes/Macrophages — attracted to early lesion, become foam cells.
• Foam cells — lipid-laden macrophages; main component of fatty streaks.
• Vascular smooth muscle cells (VSMC) — migrate inward, produce collagen and extracellular matrix (ECM).
• Fibrous cap — collagen-rich layer covering the plaque, maintaining stability.
• Lipid core — necrotic debris, extracellular lipids, foam cells.
• Thrombus — formed after cap rupture, causes occlusion.