Which process involves fat, cholesterol, and other substances building up in arterial walls to form plaques?

• A. Angioplasty
• B. Aneurysm
• C. Cardiomegaly
• D. Atherosclerosis

Answer: (D)

The process described is atherosclerosis, where fat, cholesterol, and other substances accumulate in the inner lining of arteries to form plaques. This starts with injury to the endothelium, allowing LDL cholesterol to enter the arterial wall and become oxidized. Macrophages are drawn in and ingest the lipids, turning into foam cells and creating a fatty streak. Over time, smooth muscle cells migrate into the intima and lay down connective tissue, forming a fibrous plaque that narrows and stiffens the vessel. Plaques can calcify and, if they rupture, trigger thrombosis, leading to reduced blood flow or acute events like heart attack or stroke. The other options describe different things: a procedure to open narrowed arteries (angioplasty), a ballooning of a weakened artery wall (aneurysm), and enlargement of the heart (cardiomegaly).