THE GENITOURINARY SYSTEM

THE GENITOURINARY SYSTEM

EVERY BODY cell not only must build its substance and obtain its energy from nutrients supplied in the food you eat; it must get rid of wastes. And all cells deliver their waste products continuously to the blood. In turn, the blood carries them to various centers for excretion. 

Thus, carbon dioxide and some water in the form of vapor are removed from the blood in the lungs. Salts and additional water pour out through the skin's sweat glands. Other wastes, including water, salt, urea, and uric acid-leave the blood in the kidneys. Blood enters the kidneys through the renal arteries and leaves through the renal veins and, in circulating within the two kidneys, goes through a fabulous filtering system. 

The kidneys-each about 4-1/2" long, 2-1/2" wide, 1-1/2" thick, and weighing 5 ounces-are located deep in the abdomen at about the level of the lowest ("floating") ribs. Essentially, they are filters containing intricate plumbing-a system of tiny tubes called nephrons whose combined length in each kidney is about 140 miles. To the naked eye, a single nephron would resemble a grain of sand. Under a microscope, it has the look of a twisted worm with a huge head. The head, called the glomerulus, is covered with a network of capillaries that carry blood continuously into the glomerulus. 

The tail is the tubule. In a healthy kidney, as blood enters a glomerulus, a fluid is separated from it. The fluid contains neither red, nor white blood cells nor only a trace of large protein molecules. The fluid passes along the tubule, and about 99 percent of the water, amino acids, proteins, glucose, and minerals needed by the body are returned to the bloodstream. The remaining fluid, with its content of waste materials, is eliminated from the body as urine. Every 24 hours, the kidneys filter about 200 quarts of fluid and salts.

One or two quarts of the waste go to the bladder and are flushed out of the body. Actually, the kidneys have a tremendous reserve capacity; they could clean nine times more fluid than they are called upon to do, and for this reason one healthy kidney can readily serve the body's needs. The kidneys function to maintain the correct balance between the salts and water of the body, to get rid of any toxic substances, and to keep the body in correct mineral balance. For example, too much potassium in the blood could stop the heart quite as effectively as a bullet. 

Physical fitness, excercises, health issues- health education-calories

Your exercise program should be balanced, just as diet should be balanced. You need one or more activities to exercise the heart and lungs and to build endurance. Brisk walking, jogging, and swimming relatively long distances are good for this. Other parts of the program should be aimed at improving strength, agility, flexibility, and muscle tone. Suggestions for a home exercise program to achieve these objectives can be found in such publications as these: Adult Physical Fitness. 

President's Council on Physical Fitness

Washing- ton, D.C., Supt, of Documents, U.S. Government Printing Office

Physical Fitness

Department of Health Education, American Medical Association, 535 N. Dearborn, Chicago, Ill. Seven Paths to Fitness.

Department of Health Education, American Medical Association, 535 N. Dearborn, Chicago, Ill Most people understand how. Specific exercises for various muscles and parts of the body can develop strength. These are certainly worthwhile. For some reason, one particular area of relative neglect is the abdominal muscle area. 

Another is the muscles of the back. Both are important in terms of good posture; both are important, too, as aids in avoiding sagging waistlines and backaches. We give exercises for these in this chapter along with another exercise for the muscles of the buttocks; and the four exercises, in addition to their general value, are helpful in restoring muscle tone in these areas in people who are slimming down.

But we think it important to go on at once to emphasize here the activities that exercise the heart and lungs and build endurance. 

When you are at rest, all the muscles in your body use only about one thirtieth of the oxygen they can use during maximum effort. The more oxygen they use, the more the heart will respond, pumping harder to get more oxygen- Physical Activity I 87 carrying blood into circulation. Over a period of time, as a result of this, heart pumping efficiency will increase. 

The heart will become able to pump much more blood with each stroke. At the same time, lung capacity, much of it never used in sedentary living, will increase to absorb and feed more oxygen into the bloodstream. 

WHAT SCIENCE STILL DOES NOT KNOW ABOUT FOODS? SPECIAL DIETS

SPECIAL DIETS 

Special diets can be of value for certain specific health problems. For example, a protein-free diet may be prescribed in some cases of severe kidney damage; a high-protein diet in some cases of hepatitis; a high- residue diet in cases of atonic constipation; a low-fat diet in certain diseases of the liver and gallbladder; a low-purine diet in gout; a low- sodium diet in high blood pressure, congestive heart failure, and toxemia of pregnancy; a bland diet for ulcer, gastritis, and hiatus hernia; a gluten- free diet for celiac disease and cure. 

Special dietary treatment is also an important part of the overall therapy in many cases of diabetes. Whenever a special diet may be of value, it should, of course, be prescribed by a physician on the basis of the patient's individual needs.

WHAT SCIENCE STILL DOES NOT KNOW ABOUT FOODS 

Every physician and scientist concerned with nutrition knows well that despite all that has been learned, much more remains to be. At any time, some fundamental new finding-of a previously unknown vitamin or other essential nutrient-may be made. 

At the risk of being repetitious, we would like to emphasize again that every advance to date has underscored the one fact: except in special instances, the best and healthiest diet is a balanced and generously varied diet. Nature distributes her largesse. We can be most certain of benefitting from it by making use of many rather than limited numbers of foodstuffs. Almost certainly, if we do this, we will be enjoying the values of still-undiscovered vital elements.

WEIGHT CONTROL 

WHILE THERE are nutritional diseases due to deprivation-rickets, scurvy, and others-by far the most common nutritional disease in this country is one that results from abundance. Overweight, affecting one in every five Americans, is a mammoth, chronic, frustrating problem. 

It can be called, justly, the number-one health hazard of our time. It's a remediable problem-but not, unfortunately, the way most of us choose to go about attacking it. To a much lesser extent, underweight constitutes a health problem. And the correction of both is an important function of preventive medicine. 

Heart problems and Sugar intake - Bodily reactions

SUGAR AND THE HEART 

Can consumption of large amounts of sugar be as much of a factor in coronary heart disease as cholesterol? So British investigators led by Dr. John Yudkin of the University of London maintain. They note that over the past 200 years in Great Britain sugar consumption has gone up almost 25-fold, from an average of 5 pounds per person in 1760 to 25 in 1860 and to 120 pounds in 1960. 

A sizable increase in sugar consumption in the United States also has been noted by American investigators. The British workers note that increasing affluence anywhere is accompanied by increased incidence of heart attacks and by diet changes which include greater consumption not only of fat but of sugar.

They point to studies showing that recent Yemeni immigrants to Israel have little coronary thrombosis but those who have been in Israel 20 years or more become prone to the disease-s-and the major change in their diet is increased sugar consumption. 

Among their own studies, Yudkin and his co-workers report one covering three groups of men, aged 45 to 66. Twenty had recently suffered first heart attacks, 25 had hardening of leg arteries, and 25 others had no health problems. The sugar intake of the first two groups customarily had been roughly twice that of the healthy group. 

Not all doctors agree with Dr. Yudkin. Much work remains to be done to identify the mechanism by which sugar in excess may produce artery disease. And a big question to be answered is whether reduction of sugar intake will reduce risk of artery disease. Still, even the possibility that sugar may be involved in this major disease adds another reason why moderation in its use appears warranted. Ordinary refined sugar is what nutritionists call an "empty calorie" substance. 

It provides energy-but no protein, no vitamins, no minerals. It can add to body weight but does not help the body repair itself. Sugar, as contrasted, say, with cereal, puts the body at a nutritional dis- advantage.