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Aim: How does our body come under attack? What is a disease? Disease is any condition that prevents the body from working as it should. As a result the body may fail to maintain homeostasis. What can cause disease? Lifestyle choices Genetics Toxins Organ malfunction Pathogens What are pathogens? Foreign Invaders! Types of Pathogens • Bacteria • Viruses • Fungi • Parasites Bacteria • Prokaryotes (no nucleus, missing organelles) • Unicellular (one cell) Examples: • Strep throat • Salmonella • Syphilis (STD) How can we treat bacterial infections? Antibiotics are drugs used to stop infections by bacteria. Antibiotics will not work against viruses!! SuperBugs!! Virus • A VIRUS IS NOT A CELL (IT IS NOT ALIVE) • Made of: DNA + a Coat around it Viruses are GRIMEY They can only reproduce INSIDE a cell. A virus works by injecting its DNA into YOUR cells and hijacking them It turns your cell into a virus producing factory… then causes it to explode when it’s done! Examples • HIV • Chicken Pox • Influenza (the flu) Fungus • Athlete’s foot • Ring worm What can the doctor Prescribe? Anti-fungal medicine Parasites Some animals and one-celled organisms survive by living and feeding on other organisms (their host). Example: tapeworms and heartworms How do pathogens get in your body? Air Water Contact Blood & bodily fluid Diagnosing – determine the disease you have Diagnosis is made based on symptoms and an examination Prevention vs. Treatment Prevention – ways to avoid getting the disease. Treatment – ways to help people with a disease to get better. Aim: How does our body defend us from pathogens? Flu attack! 1st Line of Defense • • • • • Skin Mucus Hair Tears in eyes Acid in stomach 2nd Line of Defense The Immune System • Made of proteins, cells, and tissues that identify and defend the body against foreign chemicals and organisms White Blood cells • Warrior Cells! • Defenders of the body • Eat the bad guys to destroy them How does our immune system identify pathogens? Antigen • A ID tag made of proteins identifies the invader as foreign • This ID tag is called an antigen. What happens after we identify the foreign invader? Our body makes antibodies, which are their weapons against the foreign antigens. Antibodies are Y-shaped weapons Antibodies Pathogen Antibodies Antigens Antibodies find the Antigens on the pathogen & targets it for destruction ! How do antibodies destroy pathogens? • When the antibody attaches to the antigen, it tears open the bad guy’s (pathogen’s) cell membrane– and the bad guy dies!!! • It also tells your immune system cells that this guy is ready to be eaten alive! How are locks & keys similar to antigens and antibodies? Antibodies are made specifically to match the shape of the antigen. Antibody vs. Antigen Antibody – weapon found in your body Antigen – ID tag found on the pathogen Our Immune System has a good memory! • Our immune system “remembers” bad pathogens it has fought in the past • It has weapons built up so the next time the pathogen enters your body, you are ready to defend yourself! The second response to the same pathogen triggers a quicker and stronger response. ** After the first response, the immune system “remembers” specific pathogens by leaving behind cells that protect the body for years (memory cells). DO NOW: What is immunity? Survivor- Tribal Immunity Immunity: When a person is protected from getting a certain disease. Aim: How does your body become immune to disease? Farms & Better Immune systems Types of Immunity Vaccines From mother Making your own antibodies to attack pathogens How was the first Vaccine developed? English physician Edward Jenner developed an inoculation against smallpox in 1796. Armed with the knowledge that milkmaids who had been exposed to cowpox, a relatively mild affliction, didn't come down with smallpox, Jenner intentionally infected an eight-year-old boy with cowpox. Two months later he infected the boy again, this time with smallpox. As Jenner expected, the child didn't come down with the disease -he was immune. What is a vaccine? Antigen Weakened Pathogen Antibody A vaccine is a dose of a pathogen destroyed so it is no longer harmful, but it still has the antigens present. These antigens trigger an immune response. How do scientists make vaccines? • http://www.pbs.org/wgbh/nova/bioterror/v accines.html 1) Obtain pathogen 2) Treat pathogen to kill or weaken it. 3) Inject altered pathogen (vaccine) into organism. 4) Body responds to antigens by 5) Some white blood cells making antibodies remain in the & having cells body to protect the organism attack invader. from future attacks. What happens when you get invaded by the real pathogen? Memory Cells are already present and will multiply quickly and destroy the invader before it has the chance to cause the disease. Memory Cells Immune response Antibody Concentration Real Pathogen Interval between exposures Vaccine First exposure Second exposure Time Bioterrorism Today there is mounting concern about the threat of a bioterrorist attack using smallpox -- so much concern that in October 2001 the American government decided to order enough vaccines to protect every U.S. citizen. Smallpox has a fearsome reputation, having killed more people in history than any other infectious disease. Aim: How can the immune system malfunction? How can your immune system malfunction? 1. 2. 3. 4. Allergies Asthma Autoimmune Disease Organ Transplants What is an allergy? • An allergy is a quick immune system reaction to substances that are normally harmless • Can you think of materials that can cause allergic reactions? What are things that cause allergies? Allergens BEE POLLEN RAGWEED HOUSE DUST MOLD Allergic reactions • Histamines are chemicals that cause inflammation • Inflammation: blood vessels get larger to send blood to area. You get Itchy, warm, red. • Hives, nausea, or shock • What can we take for allergies? https://www.youtube.com/watch?v=sqrnShjM4II&spfreload =10 Asthma is an allergic reaction • Allergic reaction that causes your respiratory system to swell up – you cant breathe well https://www.youtube.com/watch?v=7EDo9pUYvPE Autoimmune disease The immune System mistakes your own cells for the bad guys, and attacks them! Ex: Diabetes, Multiple Sclerosis https://www.youtube.com/watch?v=M7O78LvrNSQ Why are organ transplants difficult? • This is a kidney being removed from a donor • The donor will have his own ID tags on the cell membrane. What are these ID tags called? Antigens! How will the recipient react? • A transplanted organ is recognized as foreign and is attacked by the immune system (REJECTION). • The chance of REJECTION is less when the donor and recipient are closely related or when anti-rejection medication is used.