heart diseases

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heart diseases
In the United States in the next year, about 1.5 million citizens will suffer a 'heart attack', and for about one third of them it will be fatal. In New Zealand, about 8000 deaths a year a attributed to heart disease, and most of these (about 6600 in 1994) are due to ischaemia. Heart disease is a phenomenon of a 'Western' life style, associated with malnutrition, in the sense of poor dietary habits, lack of exercise and the use of drugs such as nicotine. To understand the nature of heart disease it is necessary to understand first the structure and function of the heart.

The human heart is a remarkable organ. Its essential function is to pump blood at high pressure to the rest of the body, thus providing the energy for conveying oxygen, foodstuffs and endocrine substances to where it is needed, and removing waste products of metabolism from their site of production to the kidneys and lungs, where they can be removed. The heart makes about 70 contractions per minute throughout life, pumping about 5 litres of blood per minute around the body. During extreme exercise the output of the heart can increase fivefold. The gross anatomy of the heart is shown in the picture below.