Heart Disease Essay

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Cameron Monteith L6BR
Biology ­ What is Heart Disease?
Heart disease, or cardiovascular disease, is a class of diseases that involves the heart, the blood vessels, or both.
Heart disease kills more people in the UK than any other disease. Almost half of heart disease deaths are from
coronary heart disease, killing more than 385,000 people per annum. Coronary heart disease affects the coronary
arteries, the pair of blood vessels that supply the heart muscle with the glucose and oxygen that it requires for
respiration. Blood flow through these vessels may be impaired by the build-up of fatty deposits known as atheroma.
If blood flow to the heart muscle is interrupted as a result of atheroma, it can lead to myocardial infarction. Coronary
heart disease alone costs the United States $108.9 billion each year. This total includes the cost of health care
services, medications, and lost productivity. Heart disease is not inevitable; most of it can be prevented.
One form of heart disease is called atheroma. Atheroma is a fatty deposit that forms within the wall of an artery. It
begins as fatty streaks that are accumulations of white blood cells that have taken up low-density lipoproteins
(LDL's). These streaks enlarge to form an irregular patch, called atheromatous plaque. Atheromatous plaque most
commonly occur in larger arteries and are made up of deposits of cholesterol, fibers and dead muscle cells. They
bulge into the lumen of the artery, causing it to narrow so the blood flow through it is reduced.
The heart is a vital organ, pumping blood which carries essential oxygen and nutrients all around the body. As a
powerfully active muscle, the heart needs a ready and plentiful supply of oxygen and nutrients itself; however these
are not extracted from the blood that flows through it. Instead, the heart has its own specific blood supply from the
coronary arteries. There are two major coronary arteries ­ the right and left. Unlike other organs which can use the
oxygen within veins if needed, the heart is completely reliant on the coronary arteries' supply. The volume of blood
which flows to the heart is largely determined by the width of these vessels and is not so dependent on the power at
which the blood is pumped through them. Therefore when the lumen is significantly narrowed as a result of
atheromatous plaque, the heart is starved from the oxygen and nutrients it needs from the blood supply in the
coronary arteries in order to respire. As a result this reduces its ability to function and could lead to myocardial
Furthermore, if an atheroma breaks through the endothelium of the blood vessel, it forms a rough surface and
interrupts the otherwise smooth flow of blood. This may result in the formation of a blood clot, or thrombus, in a
condition called thrombosis. This thrombus may block the blood vessel, reducing or prevent the supply of blood to
the tissues beyond it. The region of tissue deprived of blood often dies as a result of the lack of oxygen, glucose and
other nutrients the blood normally supplies. Sometimes, the thrombus becomes dislodged from the endothelium, as
is carried from its place of origin and lodges, and blocks another artery. In this form, the thrombus is called an
Atheromas that lead to the formation of a thrombus also weaken the artery walls. These weakened points swell to
form a balloon-like, blood filled structure called an aneurysm. Aneurysms frequently bust, leading to haemorrhage
and therefore loss of blood to the region of the body served by the artery. A brain aneurysm is known as a
cerebrovascular accident, or stroke.
Furthermore, a blockage in the coronary arteries reduces the supply of oxygen to the muscle (myocardium) of the
heart, known as myocardial infarction, or a heart attack. This results from a blockage in the coronary arteries. If this
occurs close to the junction of the coronary artery and the aorta, the heart will stop beating because its blood supply
will be completely cut off. The event is called "acute" if it is sudden and serious. A person having an acute myocardial
infarction usually has sudden chest pain that is felt behind the breast bone and sometimes travels to the left arm or
the left side of the neck. Additionally, the person may have shortness of breath, sweating, nausea, vomiting,
abnormal heartbeats, and anxiety. The anxiety is often described as a "sense of impending doom". In many cases, in
some estimates as high as 64%, the person does not have chest pain or other symptoms. These are called "silent"
myocardial infarctions.

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Cameron Monteith L6BR
There are a number of factors that separately increase the risk of an individual suffering from a cardiovascular
disease. One factor that significantly increases the risk of heart disease is smoking. Smokers are between two and six
times more likely to suffer from heart disease than non-smokers. This is largely because a cigarette contains a toxic
chemical called carbon monoxide. This combines easily and irreversibly with the haemoglobin in the red blood cells to
form corboxyhaemoglobin.…read more


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