What type of blood vessel is primarily involved in atherosclerosis?

Atherosclerosis primarily affects arteries because it is a condition characterized by the buildup of plaques within the arterial walls. These plaques consist of lipids, inflammatory cells, and other materials that can narrow the arterial lumen, leading to reduced blood flow and increased risk of cardiovascular events such as heart attacks and strokes.

Arteries are the blood vessels responsible for carrying oxygenated blood away from the heart to various tissues throughout the body under high pressure. When atherosclerosis develops, it typically occurs in large and medium-sized arteries, like the coronary arteries or carotid arteries, due to their exposure to high blood flow and pressure, which can contribute to endothelial injury and plaque formation.

In contrast, capillaries are small vessels where exchange of gases, nutrients, and waste occurs, and they are not involved in the disease process of atherosclerosis. Veins carry deoxygenated blood back to the heart and are generally at lower pressure, making them less susceptible to the changes that characterize atherosclerosis. Arterioles, though they branch off from arteries and lead to capillaries, are also not the primary focus of atherosclerosis, as this disease condition primarily manifests in larger arterial structures.