blood[/caption]The blood is truly the "breath of life" the living body. It takes up the oxygen from air breathed in by the lungs, and gathers all the nutritious products of the food consumed. These it distributes to all body cells through that network of smallest blood vessels, the arterial capillaries.
While carrying nourishment trough the capillaries for the tissues, the blood also collects waste products and oxidation products from the cells while flowing back through the capillary veins. The blood regulates the chemical balance (acid base balance) and the body emperature, and it defends the body against infection by means of its white blood cells and antibodies.
The blood volume amounts to about six quarts and is equal to about 1/2o of the body weight. The blood consists of a fluid portion called the plasma, and red and white blood cells suspended in the plasma. When exposed to the air, blood clots because of the action of an enzyme which combines with the calcium salts in the blood.
Centrifuging removes the fibrin and blood cells, leaving a clear, straw-colored liquid, the serum. Physician can now increase the coagulability of the blood by injecting prothrombin and calcium salts. To diminish the coagulability, they inject an opposite enzyme
called heparin. These substances are made use of in operative cases and other conditions. The blood contains about 5,000,000 red blood cells and about 8,000 white blood cells per cubic millimeter, somewhat fewer in women, in addition to calcium, sodium chloride (table salt), various proteins, hemoglobin and sugar. When the sugar content of the blood exceeds 120 milligrams per 100 cubic centimeters, it is a sign of diabetes even if there is no sugar present in the urine.
The hemoglobin of the red blood cells is a protein colored red by iron, which combines loosely with the oxygen of the lungs forming oxyhemoglobin, thus bringing oxygen to every cell of the body. Hemoglobin combined with oxygen gives a bright red color to blood in the arteries. Eighty percent of the iron in the body is found in hemoglobin. The hemoglobin content of the mature normal male is set at 100% as an arbitrary standard.
Measured by this standard the female hemoglobin is about 9o%, children about 8o%; at 21 years of age, the hemoglobin is supposed to have reached the adult level. The only way to keep the blood normal is to consume an adequate daily diet, and to have plenty of fresh air day and night.
An adequate diet consists of at least a pint of milk; one egg, one average portion of meat, fish or poultry; some butter and cheese; 4-6 slices of whole wheat or whole rye bread, a portion of a whole grain cereal like oatmeal, wheatina or brown rice; one potato and some other cooked vegetables; a green salad, as lettuce or escarole with grated carrots; an orange, one-half grapefruit, the juice of one lemon or a tomato; and liver once a week.
The portions need not be large; but the variety of foods must be maintained daily to secure the proper amount of protein and an adequate supply of the necessary vitamins and minerals. Lack of Iron in the causes of protein in the blood (hypoproreinemia) is followed by reduced resistance to infectious diseases, stomach ulcers and many other ailments
see also anemia
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