Kids Research Express

Diarrhea, frequent passage of abnormally loose, watery stool. Diarrhea usually develops suddenly and may last from several hours to a few days. It is often accompanied by abdominal pains, low fever, nausea, and vomiting. If the attacks are severe or increasingly frequent, exhaustion and dehydration can result. In normal digestion the large intestine absorbs excess water from liquid food residues produced by earlier phases of the digestive process before excreting semisolid stools. When the mucous membrane lining the large intestine is irritated or inflamed, food residues move through the large intestine too quickly and the resulting stool is watery because the large intestine cannot absorb the excess water. Diarrhea is not a disease. It is a symptom of numerous disorders, such as food poisoning from contaminated foods or beverages, infections by viruses and bacteria, or anxiety. Chronic diarrhea, which lasts weeks or months, may be caused by amoebic dysentery (intestinal infection), tu...

. Myxedema (Greek myxa, “slime”; oidema, “swelling”), deficiency disease caused by insufficient or lack of production of hormone by the thyroid gland. Patients with myxedema complain of fatigue, lethargy, sleepiness, poor tolerance to cold, mental sluggishness, a tendency to gain weight, and generalized aches and pains. Their faces often look puffy and waxy. Their skin is dry and coarse; their hair is coarse, dry, and brittle, and it tends to fall out easily. Often patients also lose the outer portion of their eyebrows. These and other symptoms are caused by a low metabolic rate resulting from a deficiency of the thyroid hormone that stimulates metabolism. Myxedema differs from cretinism in that it develops after birth and produces less severe cerebral inadequacy. The disease may occur in several members of a single family. Any condition that decreases the elaboration of thyroid gland hormone may bring on myxedema. The disease is treated by the administration of thyroxine , other t...

. Goiter, disease of the thyroid gland , characterized by an enlargement of the gland, visible externally as a swelling on the front of the neck. In simple goiter the basal metabolic rate is somewhat lowered, and in toxic goiter it is elevated. Iodine deficiency in the body can cause goiter. Treatments include the ingestion of small doses of iodine, or, in extreme cases, the removal of the thyroid gland. SIMPLE GOITER This condition is characterized by an enlargement of the entire gland, or of one of its two lobes, caused by a deficiency of iodine in the diet. The disease is especially apt to appear in adolescence. Prevention requires taking small doses of iodine for long periods. Ingestion of iodine during pregnancy prevents development of the disease in the infant as well as in the mother. Public health measures, including the addition of iodine to water supplies and to table salt, have helped to reduce the incidence of simple goiter in certain areas. Iodine is most effective when ad...

. The three main diseases of human teeth are tooth decay, also called dental caries; gum disease, or periodontal disease; and problems with tooth alignment, called malocclusions. Human teeth problems are treated or prevented by dentists, professionals who are specially trained to practice dentistry . Tooth decay affects approximately 90 percent of all children by the time they are 14 years old. Tooth decay begins when bacteria are passed from mothers or caregivers to children between their first and second birthdays. When these bacteria are exposed to sugars commonly found in foods, the bacteria produce harmful acids that attack tooth enamel. Left unchecked, the acid eats holes in the enamel and forms cavities of tooth decay. Most tooth decay forms in the deep grooves on the chewing surfaces of the molars, called pits and fissures. Daily tooth brushing and proper dental care help prevent and reduce tooth decay. Dentists use preventive treatments to reduce the risk of tooth decay; clear...

. Urologists are physicians who specialize in treating urinary system disorders. One of the most serious disorders urologists treat is renal failure, which slows or stops the filtration of blood, causing toxic waste products to build up in the blood. Acute renal failure, which occurs suddenly, may be caused by bacterial infection, injury, shock, congestive heart failure, drug poisoning, or severe bleeding following surgery. Treatment may include drugs to address the underlying cause or to stimulate proper kidney function, blood transfusions, surgery, or, in some cases, kidney dialysis , in which the blood is mechanically filtered. Chronic renal failure is a progressive deterioration of kidney function over a long period of time. It can be caused by diseases such as hypertension , diabetes, lupus erythematosus, acquired immunodeficiency syndrome (AIDS), and a form of cancer called myeloma. If diagnosed early the degenerative process can be slowed, but not reversed, by interventions tha...

Human Nutrition is learning how food affects the health and survival of the human body. Human beings require food to grow, reproduce, and maintain good health. Without food, our bodies could not stay warm, build or repair tissue, or maintain a heartbeat. Eating the right foods can help us avoid certain diseases or recover faster when illness occurs. These and other important functions are fueled by chemical substances in our food called nutrients. Nutrients are classified as carbohydrates, proteins, fats, vitamins, minerals, and water. When we eat a meal, nutrients are released from food through digestion. Digestion begins in the mouth by the action of chewing and the chemical activity of saliva, a watery fluid that contains enzymes , certain proteins that help break down food. Further digestion occurs as food travels through the stomach and the small intestine, where digestive enzymes and acids liquefy food and muscle contractions push it along the digestive tract. Nutrients are absor...

Skin Cancer, malignancy in the skin, and the most common of all cancers. There are three main types of skin cancer: basal cell carcinoma , squamous cell carcinoma, and melanoma. Basal cell carcinoma, the most common type, develops in the basal, or bottom, layer of the epidermis, the top layer of skin. Squamous cell carcinoma, the second most common type, develops in the upper layers of the epidermis. The third type of skin cancer is melanoma. It develops in the melanocytes, or pigment cells, which are found throughout the basal layer. Melanoma is the most dangerous type of skin cancer and is responsible for about three-quarters of all skin cancer deaths. Skin cancers can grow in any part of the skin, but approximately 90 percent develop in areas exposed to the sun, especially the face, neck, backs of the hands, and the scalps of bald men. Exposure to direct sunlight, especially during childhood, is the chief risk factor for skin cancer, and the greater the number of blistering sunburns...