health

The buildup of plaque that leads to coronary artery disease can start as early
as childhood. Arteries in the human body are blood vessels that carry blood
away from the heart, in contrast to veins, which carry blood toward the
heart. Arteries have three layers of tissue: an outer layer made of connective
tissue, a middle layer made of smooth muscle, and a thin inner layer of cells
that serve as a lining to the artery. This inner layer smoothes the flow of
blood, which allows the heart to pump the blood further. The coronary
arteries branch off from the base of the aorta, the large trunk artery at the top
of the heart. They are the only source of blood supply to the heart muscle
itself, which is why a blockage in these arteries is such a critical situation.
If the thin inner layer of a coronary artery is damaged, the body tries
to heal it by covering it with a layer of plaque. Over time, the plaque
deposit can become thicker, to the point where blood no longer flows
smoothly through that part of the artery and the heart muscle becomes
ischemic. Ischemia is a condition in which a portion of heart muscle (or
any other tissue) is not receiving enough blood because of the blockage
of an artery that ordinarily supplies it with blood. Ischemia in the heart can
lead to angina—a type of chest pain that feels like squeezing or pressure
and can move from the chest area to the arms, neck, jaw, or back.
The plaque deposits within the damaged artery can also rupture or
crack open. Blood cells called platelets move to the ruptured area and
form blood clots that block the artery. The loss of the blood supply following
the closure of the artery leads to the death of heart tissue. The
death of part of the heart muscle is called a heart attack, which doctors
call a myocardial infarction or MI.