Warm Up Why is mucous important and where is it specifically produced? List the 2 types of defense for the body 3. Why should you not treat a moderate fever?

THINK ABOUT IT For thousands of years, people believed that diseases were caused by curses, evil spirits, or vapors rising from foul marshes or dead plants and animals. In fact, malaria was named after the Italian words mal aria, meaning “bad air.” This isn’t all that surprising, because, until microscopes were invented, most causes of disease were invisible to the human eye!

There are 2 general defenses to fight infection: Nonspecific and Specific

First Line of Defense: Skin The skin is a tough, waterproof barrier that is hard to penetrate. Areas not covered by skin (mouth, nose, and eyes) are protected by : Saliva, mucus, and tears contain lysozyme, an enzyme that breaks down bacterial cell walls. Mucus in your nose and throat traps pathogens. Then, cilia push the mucous-trapped pathogens away from your lungs. Stomach secretions destroy pathogens that are swallowed.

Second Line of Defense: Inflammation Response If pathogens make it into the body, through a cut in the skin, for example, the body’s second line of defense swings into action. These mechanisms include the inflammatory response, the actions of interferons, and fever. 1. Histamines increase the flow of blood and fluids to the affected area.

Inflammatory Response 2. Fluid leaking from expanded blood vessels causes the area to swell. 3. White blood cells move from blood vessels into infected tissues.

4. Many of these white blood cells are phagocytes, which engulf and destroy bacteria. All this activity around a wound may cause a local rise in temperature. That’s why a wounded area sometimes feels warm.

5. Interferons: proteins which block viral infections and slow down the progress of infection and “buy time” for specific immune defenses to respond 6. Fever: talk with buddy and explain

Specific Defenses: The Immune System The immune system’s specific defenses distinguish between “self” and “other,” and they inactivate or kill any foreign substance or cell that enters the body. Once the immune system recognizes invaders as “others,” it attacks and remembers enabling a more rapid and effective response if that same pathogen or a similar one attacks again.

Warm up 1. Describe the 3 levels of defense for the body. Give an example of each Why do autoimmune diseases occur? 3. Why is the second exposure to an antigen more effective than the first?

Antigens: foreign substance that can stimulate an immune response. Who responds? 1. Macrophage: Large WBC that swallows antigen 2. Antibodies: tag antigens for destruction by immune cells. Antibodies may be attached to particular immune cells or may be free-floating in plasma. Body makes up to 10 billion different antibodies 3. Lymphocytes: B cells and T cells

Immune Responses humoral immunity defends against antigens in body fluids, such as blood and lymph cell-mediated immunity defends the body against viruses, fungi, and single-celled pathogens.

Immunity Why was it that milkmaids who had cowpox did not come down with deadly smallpox? Acquired immunity= vaccinations stimulate the body with deliberate exposure to an antigen to produce memory B and T cells. This causes a quick and effective response to repeated infection Passive immunity= temporary immunity from mom or by exposure to animals with the disease

Diseases Viral- spread by a virus and can not be cured only slowed with interferon. Vaccines prevent virus infection through acquired immunity. (HIV, Herpes, Ebola) Some cause cancer (HPV) Bacterial- spread by bacteria and/or it’s toxin. Most can be cured by antibiotics but some are becoming resistant. (TB, Plague, MRSA) Autoimmune diseases- body overreacts to antigen on our cells and destroys our cells. (Diabetes 1, rheumatoid arthritis, lupus)