Структура и заболевания сердца

| Категория реферата: Рефераты по медицине
| Теги реферата: предмет курсовой работы, мир докладов
| Добавил(а) на сайт: Jera.

This disease most commonly starts between the age of 5 and 19 but can occur at any age. It is the result of rheumatic fever, a combination of a streptococcal infection and an allergic sensitivity to streptococcal germs.
It is responsible for most heart disease in individuals under the age of
20.
Early indications of rheumatic fever may be a state of fatigue, poor appetite, failure to gain weight, paleness, and anemia.
It is estimated that 50 percent of those who are diagnosed in adulthood as having chronic rheumatic heart disease never realized they had experienced attacks of rheumatic fever as children. The disease causes an inflammation of the heart muscles and heart valves, and scars the valves so that they do not perform normally. The damage may prevent the valves from opening or closing properly. Rheumatic fever is controlled by regular doses of penicillin and sulfa drugs, particularly in adolescents and young adults.

Bacterial Endocarditis

This is a bacterial infection of the lining of the heart (endocardium) and the valves which may follow rheumatic fever and also may occur in persons with congenital defects of the heart. Bacteria, usually of the streptococcus family, can enter the blood stream after operations on the mouth, throat, nose, or intestines. If the microbes reach defective heart valves, they can grow on them and cause a dangerous illness. That is why persons with a history of rheumatic fever or those with congenital heart abnormalities may be given penicillin or sulfa drugs before undergoing certain operations or tooth extractions.
There are two forms of the disease, acute and subacute, with the subacute form or more common. The acute type strikes the person suddenly and can be fatal within a few days if immediate treatment is not given. Treatment includes bed rest and antibiotics.
Coronary Insufficiency.
Coronary insufficiency is a term applied to heart difficulties in which the blood flow in the coronary arteries which nourish the heart muscle itself may be decreaced.Atherosclerosis ,a common form of hardening of the arteries, may produce this condition by thickening or narrowing the walls of the coronary arteries.When the arteries are narrowed, less blood and less oxygen are carried to the heart musclemen.One form of such insufficiency is ANGINA PECTORIS, in which the coronary arteries temporarily do not provide the necessary blood to the heart muscle. The amount of blood to the heart muscle may be adequate for periods of rest or mild activity. Under conditions of emotional stress or increased physical exertion, the supply may be insufficient for the added work of the heart, and pain will result. The characteristic pain has been described as crushing or viselike and located near the left breast. The pain may fan out to the left arm and left fingers. Treatment consists of rest, nitroglycerin tablets under the tongue, or inhalation of amylnitrite.

Heart Failure

Heart failure does not mean that the heart has stopped, but that its pumping efficiency has lessened. Two types of failure can interfere with normal circulation. In one, circulatory, or forward, failure, the heart is unable to pump enough oxygenated blood to the tissues because a severe hemorrhage may cause the blood volume to fall, or because the heart is not capable of supplying the tissues with sufficient blood.
In the second type of failure, known as cardiac insufficiency ( backward, or congestive, failure), the heart muscle loses its normal vigorous beat and fails to propel the blood out of the heart chambers as swiftly as it enters them. As a consequence of the slowing of circulation, body fluids collect in the tissues. The ankles may swell, and the individual may be short of breath because of fluid in the lungs. There may be various types of indigestion from congestion of the liver and other abdominal organs.
This type of heart failure may develop after a severe heart attack or rheumatic fever, after a long period of untreated high blood pressure, or in connection with a congenital heart defect.
In circulatory failure, the victim is pale and listless, and visible veins sag. In cardiac insufficiency, the victim’s skin has a bluish tinge, the jugular vein is swollen, and he breathes noisily. The blueness stems from the fact that not enough oxygen is being supplied to the arterial blood , and the tissues also lack sufficient oxygen, while carbon dioxide mounts in the cells.
Treatment for heart failure includes rest, a special diet with lowered salt intake, medication(digitalis) to strengthen heart action, and diuretic medicines to control the excess of fluid.

Related Disorders

Hardening of the arteries and high blood pressure (hypertension) are two of the most common forms of diseases affecting the heart, and are found most frequently in the middle-aged or elderly person. The conditions may be present separately, although they are frequently associated. In the first, atherosclerosis, the walls of the arteries, and particularly the internal lining called the intima, may become roughened. Fatty deposits begin to collect. Fibrotic materials, and sometimes calcium, coat these deposits, and help to form what are known as atherosclerotic plaques. The damage spreads into the media, the muscular-elastic part of the artery, and causes loss of resiliency. These plaques fill the passageway, and gradually obstruct the flow of the blood. As the arterial walls are narrowed, it becomes more difficult for the blood to flow through the vessel.
Rise in blood pressure may be caused by a variety of factors, including emotional stress. In 90 percent of the cases, the specific cause remains undiscovered. It is believed that high blood pressure helps to speed the processes of hardening of the arteries and other blood vessel diseases.
Hardening of the arteries and high blood pressure are chiefly responsible for STROKES (Known as celebrovascular accidents), which are caused by clogging or hemorrhaging of an artery in the brain or in an artery in the neck leading to the brain. The walls of an artery may have lost their smoothness and elasticity and collected the deposits typical of hardening of the arteries, or the artery may have been clogged by a blood clot from the heart. An area of the brain to which the blood supply has been interrupted is injured, as a result of which some muscular function controlled by the brain cells may be temporarily or permanently lost.
Another disease related to diseases of the heart and blood vessels is
NEPHRITIS (Bright’s disease), or inflammation of the kidneys, which can cause high blood pressure. The heart works under the high pressure handicap, as in other types of hypertension. An acute attack of nephritis may so injure the capillaries, the tiniest blood vessels, that fluid settles in the tissues, causing swelling in various parts of the body.

Prevention and Care

Guarding against heart ailments involves a reasonable consideration for the amount of work the heart is accustomed to doing. For example, a man over 40 should remember that a burst of unusual physical work or strenuous sport creates a strain on a heart that is accustomed only to a sedentary life.
Extra weight places an extra burden on the heart. Fears of heart trouble can also be harmful. It is wise to have regular medical check-ups, and take intelligent care of one’s health, and to maintain a sensible approach to life between examinations. This includes avoiding excessive use of tobacco, following a well-balanced diet, taking regular exercise, and maintaining a good balance between work, social life and rest.

`