Atherosclerosis invades both the superficial and deep layers of the vessel walls.
Arteriosclerosis occurs over a period of many years during which the arteries of the cardiovascular system develop areas which become hard and brittle. Vessels become thickened. There is a loss of elasticity. It can involve the arteries of the cardiovascular system, the brain, kidneys, upper and lower extremities. This occurs because of the deposition of calcium in their walls.