Atherosclerosis is the build-up of fatty material (such as cholesterol), fibrous material and calcium). The build-up forms an atheroma (degeneration of the walls of the arteries) under the endothelium (cells that line the interior surface of blood vessels).
As the atheroma continues to build up it causes a number of things to happen:
the artery loses its elasticity
the blockage restricts blood flow due to the decreased diameter of the lumen
the restricted blood flow increases blood pressure
Atherosclerosis can lead to various cardiovascular diseases such as angina, heart attack, stroke, and peripheral vascular disease (PVD).