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Biology 202
2004 First Web Paper
On Serendip
Part of maintaining a healthy lifestyle is to know, at each stage of one's life, what diseases or dangers one faces. Infants, for example, are extremely susceptible to colds because their immune systems are not fully developed. Children under the age of 10 have a very high chance of getting the chicken pox. Men and women between the ages of fifteen and twenty-five are at high risk of becoming infected with HIV/AIDS. Adults over the age of forty become increasingly at risk for having a heart attack. Since February is American Heart Month, I thought this would be an excellent time to research some of the causes and effects of heart attacks.
A heart attack is caused by the build-up of fatty substances, cholesterol, calcium and other substances that make up plaque. Plaque can begin to build up within the inner linings of the larger arteries of the body in childhood, but it takes much longer, usually thirty years or more, for the build-up to escalate to dangerous levels. This process of plaque build-up is called atherosclerosis, a process which is quickened by having high blood pressure or cholesterol, diabetes or especially by smoking.
Over time the build-up of plaque severely limits the flow of blood to the heart, specifically to the myocardium, the middle layer of the wall of the heart (the outer layer is called the epicardium, and the inner layer is the endocardium). The myocardium is the main muscle which allows blood to flow in and out. In fact, according to the American Heart Association, "the medical term for a heart attack is myocardial infarction." (1)
Because less blood is getting through to the heart, oxygen, which is carried within the blood cells, also becomes limited. If one or more artery (arteries) becomes completely blocked, a heart attack follows. If immediate treatment, usually surgery to clear up the arteries, is not administered, the muscles of the heart become permanently injured, causing the patient to die or become disabled.
A heart attack can, less frequently than by the complete blocking of the arteries, also be caused by a severe spasm or tightening of the coronary artery, which temporarily cuts off blood flow from the heart. While causes of artery spasms are not widely agreed upon, it is believed that they may be caused by smoking cigarettes, heightened stress, or by taking certain illegal drugs like cocaine. (2)
Warning signs of a heart attack are varied and usually do not precede an attack by more than five minutes, so it is necessary to act quickly. Some such warning signs are prolonged or recurring (over the time period of a few minutes) discomfort or irritation in the chest or arms, shortness of breath, which is usually proceeded by the afore-mentioned discomfort, or a feeling of being lightheaded.
Treatments for heart attacks vary depending on severity of the condition and how far in advance the condition was discovered. Most common is an angioplasty procedure, which is when a small tube is placed inside an artery in order to reinstate and facilitate blood flow to the heart. Medications likewise vary from case to case, but most commonly, beta blockers are given to patients to, according to the National Heart, Lung and Blood Institute, "decrease the workload on your heart ... [and] to prevent additional heart attacks." (3)
A new treatment is emerging now for preventing heart attacks years before they start. In November 2003, Dr. Eric Topol of the Cleveland Clinic and his team of scientists were able to locate the first gene known to directly cause heart attacks. This discovery was found with the help of an Iowan family, the Steffensens, which had suffered from heart attacks for generations.(4) Out of ten siblings, nine had their first heart attack between the ages of 59 and 62, and many have had more than one heart attack. And the one sibling exempt from the heart attacks was found not to have the gene. This particular gene "creates weak artery walls", which make heart attacks a practical guarantee. And now that the gene has been identified, it can be isolated and prevented from spreading.
1 )American Heart Association Online
2 )National Heart, Lung and Blood Institute
3 )National Heart, Lung and Blood Institute
4 )CBS News
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