What characterizes atherosclerosis?

Atherosclerosis is specifically characterized by the accumulation of plaques within the arterial walls. These plaques are composed of fats, cholesterol, calcium, and other substances found in the blood. As these plaques develop, they lead to a thickening and hardening of the arteries, which can significantly impede blood flow. This condition can raise the risk of cardiovascular events, such as heart attacks and strokes.

The process begins with damage to the endothelium, the inner lining of blood vessels, which can be influenced by factors like high blood pressure, high cholesterol, smoking, and diabetes. Following this damage, inflammatory processes are set in motion, leading to the deposition of lipids and cell debris, which collectively form the plaques characteristic of atherosclerosis.

While inflammation of blood vessels does occur during atherosclerosis, it is the plaque buildup that is the hallmark of the disease itself. Other options, such as narrowing of airway passages or severe dehydration in the arteries, do not pertain to atherosclerosis, as they refer to different medical conditions. Therefore, the defining feature accurately pointed out in the answer is the buildup of plaque on the walls of blood vessels, which encapsulates the fundamental problem in atherosclerosis.