Figure 18.22: Atherosclerosis is sometimes referred to ashardeningof the arteries; plaque
build-up reduces the blood flow through the artery. ( 24 )
circulation in the brain can cause astroke. According to the American Heart Association,
atherosclerosis is a leading cause of CVD.
Coronary Heart Disease
Cardiac muscle cells are fed by the coronary arteries. Blocked flow in a coronary artery can
result in a lack of oxygen and the death of heart muscle. Coronary heart diseaseis the
end result of the buildup of plaques within the walls of the coronary arteries. Coronary heart
disease often does not have any symptoms. A symptom of coronary heart disease is chest
pain. Occasional chest pain, calledangina can happen during times of stress or physical
activity. The pain of angina means the heart muscle fibers need more oxygen than they are
getting.
Most people with coronary heart disease often have no symptoms for many years until they
have a heart attack.A heart attackhappens when the blood supply to a part of the heart
is blocked. The cardiac muscle that depends on the blood supply from the blocked artery
does not get any oxygen. Cardiac muscle fibers that is starved of oxygen for more than
about five minutes will die. Cardiac muscle does not divide, so dead cardiac muscle cells are
not replaced. Coronary heart disease is the leading causes of death of adults in the United
States. How a blocked coronary artery can cause a heart attack, and cause part of the heart
muscle to die is shown inFigure18.23. Injured cardiac muscle does not contract as well as
healthy tissue, so the heart will not work as well as it used to.