Hardening of an artery?

• A. Atherosclerosis
• B. Aneurysm
• C. Thrombosis
• D. Myocardial infarction

Answer: (A)

Hardening of the arteries is best explained by atherosclerosis, an arterial disease in which lipid-rich plaques form in the inner wall (tunica intima) of arteries, causing stiffness and narrowing. Endothelial injury or dysfunction allows LDL to enter the vessel wall and become oxidized, attracting macrophages that engulf lipids to form foam cells and create a fatty streak. Over time, this evolves into fibrous, calcified plaques with smooth muscle cell proliferation and extracellular matrix, which reduces elasticity and narrows the lumen. This combination of rigidity and reduced flow sets the stage for downstream ischemia and potential clinical events. The other conditions describe different processes: an aneurysm is a dilation from wall weakness, thrombosis is clot formation within a vessel, and myocardial infarction is tissue death from acute ischemia usually due to occlusion—none of which essentially describe the hardening characteristic of atherosclerosis.