The Immune Systems Answer Key

ANSWER KEY Biology – Unit #9c: Human Body Systems – The Immune System Study Guide 1. Compare and contrast B Cells, T Cells and Macrophages, in terms of normal percent of blood and function. Macrophage: • Nonspecific • Eats pathogens WBC B Cell • Produces antibodies Specific defense T Cell • Activates B Cells & Killer T Cells (Helper) • Destroys infected cells (Killer) 2. What is the difference between nonspecific versus specific defenses? Nonspecific immune defenses will protect the body from any pathogen. Examples of nonspecific immune defenses are skin, mucus membranes, mucus, anti-microbial proteins, nose hair, stomach acid and macrophages. Specific immune defenses will fight a specific pathogen. 3. Give 3 examples of your 1st line of defense. How do these work to protect you? Give 3 examples of your 2nd line of defense. How do these work to protect you? 1st Line: Skin, mucus, mucous membranes, Stomach acid, sweat, oil, wax 2nd Line: Macrophages, Neutrophils, Natural Killer Cells 3rd Line: Helper T cells, Killer (Cytotoxic) T Cells, B Cells, Antibodies 4. Why is a macrophage part of your specific and non-specific defenses? Macrophages are part of both the nonspecific and specific immune defenses because the will destroy cells that are infected with any type of pathogen, but they activate helper T cells and start the specific immune response. 5. Explain the difference between a pathogen, parasite and an antigen. A pathogen is any biological agent that causes damage to cells & causes disease. A parasite is an organism that lives in or on a host and feeds on its host. An antigen is a marker protein on the cell membrane. 6. How are Helper T-cells different from Cytotoxic (Killer) T-cells in the way they defend your body? Helper T cells activate the killer T cells & B cells, but they do not directly fight off pathogens. Killer T cells destroy cells that have been infected by specific pathogens. 7. How are B-cells involved in your specific defense? What are antibodies? B cells produce antibodies that are specific to each pathogen. Antibodies that bind to the antigen on a pathogen, preventing the pathogen from entering body cells. 8. What are the 5 main types of pathogens? List them and explain their differences in cell type, cell structure and energy sources. Kingdom Example Transmission Treatment/Prevention Bacteria E. coli, salmonella Direct contact (usually Wash food before preparing, contaminated food) rest, antibiotics Protozoa giardia Contact with contaminated water Fungi ringworm, athletes’ foot Direct contact with fungus Antifungal creams or oral medication Plant generally causes allergic Often airborn Antihistamines reactions Animal tape worm, round worm Eating contaminated food 9. What are Prions and Viruses? Why are they not classified in a Kingdom? Give examples of pathogens in each of the Kingdoms. Prions – proteins that cause damage to cells, ex: Mad Cow Disease (no treatment known) Viruses – DNA molecules surrounded by a protein coat, ex: influenza (prevented by vaccines) Neither prions nor viruses are able to reproduce, maintain homeostasis, or metabolize, so they are not considered to be living things 10. Explain the difference between immunodeficiency and autoimmunity? Give examples of each of these disorders. Immunodeficiency results in a weakened immune system that cannot respond well to pathogens. Autoimmunity occurs when the immune system attacks the body’s own cells. 11. Explain the difference between a vaccine and an antibiotic. When and why would each of these be given to a person? How do human diseases caused by bacteria and diseases caused by viruses react to antibiotics? Vaccine – prevents infections (usually for viruses) Antibiotics – treats a bacterial infection by killing bacterial cells by interfering with cellular processes (does work for viruses, which do not have cells) 12. Explain how a vaccine works to promote production of antibodies. A vaccine contains antigens from a pathogen that cause the immune system to produce killer T cells & B cells 13. You are exposed to a virus on this paper. Draw a picture showing the immune system cells involved in your bodies response. 14. Other than a flu shot, what are 3 ways to prevent the flu virus from causing your immune system to react? Wash your hands regularly, avoid contact with infected people, do not share food or drinks with others, etc…