Making healthy lifestyle choices can help prevent some types of cancer. For example, you can reduce your risk of lung cancer by not smoking. You can reduce your risk of skin cancer by using sunscreen (see Figure 21.6).
Diabetes is another type of noninfectious disease. Diabetes occurs when the pancreas doesnt make enough insulin or else the bodys cells are resistant to the effects of insulin. Insulin is a hormone that helps cells absorb glucose from the blood. When there is too little insulin or cells do not respond to it, the blood contains too much glucose. High glucose levels in the blood can damage blood vessels and other cells in the body. The kidneys work harder to filter the extra glucose from the blood and excrete it in urine. This leads to frequent urination, which in turn causes excessive thirst. Watch this short video for an animated introduction to diabetes, its causes, and its consequences: MEDIA Click image to the left or use the URL below. URL: There are two main types of diabetes: type 1 diabetes and type 2 diabetes. The two types of diabetes have different causes.
type 1 diabetes
Type 1 diabetes is caused by the immune system attacking and destroying normal cells of the pancreas. As a result, the cells can no longer produce insulin. Why the immune system acts this way is not known for certain. Its possible that a virus may trigger the attack. This type of diabetes usually develops in childhood or adolescence. At present, there is no known way to prevent the development of type 1 diabetes. However, it is a treatable disease. Treatment of type 1 diabetes includes: taking several insulin injections every day or using an insulin pump (see Figure 21.7). monitoring blood glucose levels several times a day. eating a healthy diet that spreads out carbohydrate intake throughout the day. regular physical activity, which helps the body use insulin more efficiently. regular medical checkups.
type 2 diabetes
Type 2 diabetes is much more common than type 1 diabetes. Type 2 diabetes occurs when body cells no longer respond normally to insulin. The pancreas still makes insulin, but the cells of the body cant use it. Being overweight and having high blood pressure increase the chances of developing type 2 diabetes. This type of diabetes usually develops in adulthood. However, it is becoming more common in teens and children because more young people are overweight now than ever before. You can greatly reduce your risk of developing type 2 diabetes by maintaining a healthy body weight. Some cases of type 2 diabetes can be cured with weight loss. However, most people with the disease need to take medicine to control their blood glucose. Regular exercise and balanced eating also help. Like people with type 1 diabetes, people with type 2 diabetes must frequently check their blood glucose.
Cancer is a disease in which cells divide out of control. Normally, the body has ways to prevent cells from dividing out of control. However, in the case of cancer, these ways fail. The rapidly dividing cells may form a mass of abnormal tissue called a tumor. This is illustrated in Figure 21.4. Watch this video for an animated introduction to cancer: . MEDIA Click image to the left or use the URL below. URL: As a tumor increases in size, it may harm normal tissues around it. Sometimes cancer cells break away from a tumor. If they enter the bloodstream, they are carried throughout the body. Then the cells may start growing in other tissues. This is usually how cancer spreads from one part of the body to another. Once this happens, cancer is very hard to stop.
causes of cancer
Most cancers are caused by mutations. Mutations are random errors in genes. Mutations that lead to cancer usually occur in genes that control the cell cycle. Because of the mutations, abnormal cells are allowed to divide. Some mutations that lead to cancer may be inherited. However, most of the mutations are caused by environmental factors. Anything in the environment that can cause cancer is called a carcinogen. Common carcinogens include certain chemicals and some types of radiation. Many different chemicals can cause cancer. For example, tobacco contains dozens of chemicals, including nicotine, that have been shown to cause cancer. Figure 21.5 shows some of these chemicals. Smoking tobacco or using smokeless tobacco increases the risk of cancer of the lung, mouth, throat, and urinary bladder. Types of radiation that cause cancer include ultraviolet (UV) radiation and radon. UV radiation is part of sunlight. It is the leading cause of skin cancer. Radon is a naturally occurring radioactive gas that escapes from underground rocks. It may seep into the basements of buildings. It can cause lung cancer.
most common types of cancer
Cancer occurs most often in adults, especially adults over the age of 50. The most common types of cancer in adults differ between males and females. The most common type of cancer in adult males is cancer of the prostate gland. The prostate gland is part of the male reproductive system. About one third of all cancers in men are prostate cancers. The most common type of cancer in adult females is cancer of the breast. About one third of all cancers in women are breast cancers. In both men and women, the second most common type of cancer is lung cancer. Most cases of lung cancer develop in people who smoke. Childhood cancer is rare. The main type of cancer in children is leukemia. It makes up about one third of all childhood cancers. It occurs when the body makes abnormal white blood cells.
diagnosing and treating cancer
Many cases of cancer can be cured if the cancer is diagnosed and treated early. Treatment often involves removing a tumor with surgery. This may be followed by other types of treatments. These treatments may include drugs and radiation, both of which target and kill cancer cells. Its important to know the warning signs of cancer so it can be diagnosed as early as possible. Having warning signs doesnt mean that you have cancer, but you should check with a doctor to be sure. Warning signs of cancer include: a change in bowel or bladder habits. a sore that doesnt heal. unusual bleeding or discharge. a lump in the breast or elsewhere. frequent, long-term indigestion. difficulty swallowing. obvious changes in a wart or mole. persistent cough or hoarseness.
immune system diseases
The immune system is the body system that normally fights infections and defends against other causes of disease. When the immune system is working well, it usually keeps you from getting sick. But like any other body system, the immune system can have problems and develop diseases. Two types of immune system diseases are autoimmune diseases and allergies.
An autoimmune disease is a disease in which the immune system attacks the bodys own cells. Why this happens is not known for certain, but a combination of genetic and environmental factors are likely to be responsible. Type 1 diabetes is an example of an autoimmune disease. In this case, the immune system attacks cells of the pancreas. Two other examples are multiple sclerosis and rheumatoid arthritis. In multiple sclerosis, the immune system attacks nerve cells. This causes weakness and pain that gradually get worse over time. In rheumatoid arthritis, the immune system attacks joints. This causes joint damage and pain. These diseases cant be prevented and have no known cure. However, they can be treated with medicines that weaken the immune systems attack on normal cells.
An allergy is a disorder in which the immune system responds to a harmless substance as though it was a pathogen. Any substance that causes an allergy is called an allergen. The most common allergens are pollen, dust mites, mold, animal dander, insect stings, latex, and certain foods and medications. To see in greater detail how allergies occur, watch this animated video: . MEDIA Click image to the left or use the URL below. URL: Did you ever hear of hay fever? Its not really a fever, and it may have nothing to do with hay. Its actually an allergy to plant pollens. People with this type of allergy generally have seasonal allergies that come back year after year. Symptoms commonly include watery eyes and nasal congestion. Ragweed, shown blooming in Figure 21.8, causes more pollen allergies than any other plant. Allergy symptoms can range from mild to severe. Mild symptoms might include itchy eyes, sneezing, and a runny nose. Severe symptoms can cause difficulty breathing, which may be life threatening. Keep in mind that it is the immune system and not the allergen that causes the allergy symptoms. Allergy symptoms can be treated with medications such as antihistamines. Severe allergic reactions may require an injection of the hormone epinephrine. These treatments lessen or counter the immune systems response. Often, allergy symptoms can be prevented. One way is to avoid exposure to the allergens that cause your symptoms. If you are allergic to pollen, for example, you can reduce your exposure by staying inside when pollen levels are highest. Some people receive allergy shots to help prevent allergic reactions. The shots contain tiny amounts of allergens. After many months or years of shots, the immune system gets used to the allergens and no longer reacts to them.
No diagram descriptions associated with this lesson
Cancer in childhood is rare.
--> a. true b. false
Warning signs of cancer include difficulty swallowing.
--> a. true b. false
Surgery is the only way to treat cancer.
a. true --> b. false
Type 1 diabetes usually develops in childhood or adolescence.
--> a. true b. false
Your risk of developing type 2 diabetes is greater if you are overweight.
--> a. true b. false
In multiple sclerosis, the immune system attacks the joints.
a. true --> b. false
Hay fever is a noninfectious disease characterized by a high fever.
a. true --> b. false
__mass of abnormal tissue formed by cancer cells
a. autoimmune disease b. carcinogen c. cancer d. noninfectious disease e. allergen f. diabetes --> g. tumor
__any disease that is not contagious
a. autoimmune disease b. carcinogen c. cancer --> d. noninfectious disease e. allergen f. diabetes g. tumor
__disease in which the level of glucose in the blood is too high
a. autoimmune disease b. carcinogen c. cancer d. noninfectious disease e. allergen --> f. diabetes g. tumor
__anything in the environment that may cause cancer
a. autoimmune disease --> b. carcinogen c. cancer d. noninfectious disease e. allergen f. diabetes g. tumor
__any substance that may cause an allergy
a. autoimmune disease b. carcinogen c. cancer d. noninfectious disease --> e. allergen f. diabetes g. tumor
__disease in which cells divide out of control
a. autoimmune disease b. carcinogen --> c. cancer d. noninfectious disease e. allergen f. diabetes g. tumor
__any disease caused by the immune system attacking the bodys own cells
--> a. autoimmune disease b. carcinogen c. cancer d. noninfectious disease e. allergen f. diabetes g. tumor
Causes of noninfectious diseases include
a. environmental toxins. b. gene mutations. c. pathogens. --> d. two of the above
Mutations that lead to cancer usually occur in genes that control the
--> a. cell cycle. b. production of insulin. c. development of the lungs. d. maturation of the reproductive organs.
Common carcinogens include
a. nicotine. b. UV light. c. radon gas. --> d. all of the above
The most common type of cancer in adult males is cancer of the
a. adrenal gland. b. thyroid gland. c. pituitary gland. --> d. prostate glan
The second-most-common type of cancer in adult males and females is cancer of the
a. stomach. b. liver. --> c. lung. d. kidney.
All of the following are autoimmune diseases except
a. type 1 diabetes. --> b. type 2 diabetes. c. multiple sclerosis. d. rheumatoid arthritis.
a. never life threatening. b. autoimmune diseases. --> c. commonly caused by pollen. d. two of the above
No diagram questions associated with this lesson