Physiology encompasses the tissue, organ and cellular functions of the human body. An optimally healthy body has normal physiology. Conversely, human disease represents an aberration in normal physiology--something in the body fails to function as it should. Normal physiology can be disrupted by a variety of mechanisms, ultimately manifesting as disease. Hemochromatosis, iron-deficiency anemia and iron-reutilization anemia exemplify different types of physiological abnormalities that can affect body systems, leading to disease.
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Hemochromatosis is a physiological disease of iron absorption and storage. With this disease, the intestines absorb excessive quantities of dietary iron. Because the body has no mechanism to excrete excess iron, the mineral accumulates in the organs of the body, especially the liver, pancreas, heart, ovaries or testicles and other hormone-producing glands.
Over time, excess iron in the body tissues provokes cellular damage and scarring, compromising organ function. Cirrhosis, type 1 diabetes mellitus, joint damage and heart failure may develop with untreated hemochromatosis, reports the National Institute of Diabetes and Digestive and Kidney Diseases. Treatment of hemochromatosis involves therapeutic removal of blood from the circulation to rid the body of excess iron.
Whereas hemochromatosis demonstrates the deleterious effects of too much iron on human physiology, too little iron is also harmful, albeit in different ways. Humans require a small amount of dietary iron to compensate for ordinary losses through cell turnover. Abnormal bleeding or inadequate iron intake can deplete body iron stores, resulting in a deficiency of this essential mineral.
Red blood cell production requires iron. Inadequate iron slows bone marrow production of the oxygen-carrying red blood cells, leading to anemia. Anemia has immediate effects on multiple organ systems, affecting essential body functions such as heart rate, respiratory rate and muscle metabolism. Chronic iron-deficiency anemia may cause permanent heart damage, reports the National Heart, Lung and Blood Institute. Treatment of iron-deficiency anemia involves supplemental iron to restore body stores of the mineral, and treatment of any underlying conditions that may have contributed to the development of the deficiency.
Chronic inflammatory and infectious diseases or cancer can disrupt the body's capacity to use iron normally, leading to a disease known as iron-reutilization anemia, or anemia of chronic disease. With this disease, iron levels may be normal but chemicals released in response to the underlying condition disrupt the mechanisms that regulate iron utilization and bone marrow production of red blood cells. Manufacture of red blood cells decreases due to these physiological disruptions, resulting in anemia. Treatment of iron-reutilization anemia focuses on correction of the underlying condition, which removes the disturbances interfering with normal red blood cell production.
- National Institute of Diabetes and Digestive and Kidney Diseases: Hemochromatosis
- National Heart, Lung and Blood Institute: Iron-Deficiency Anemia
- Merck Manual for Healthcare Professionals: Anemia of Chronic Disease (Iron-Reutilization Anemia)
- WebPath, The Internet Pathology Laboratory for Medical Education: Diseases of Iron Metabolism
- "Harrison’s Principles of Internal Medicine, 16th Edition"; Dennis L. Kasper, M.D., et al., editors; 2004