9 Science Revision Topics PDF
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Uploaded by RealizablePlatypus2375
Harvard Junior High
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Summary
This document covers important concepts from the topic of vaccination, and introduces the immune system and explains some of the physical and chemical barriers to infection. The document provides key information on vaccinations and immune response.
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How vaccines work- **Vaccines teach the immune system how to recognize and remember the pathogen and fight off specific disease-causing germs**. Signs of infection -- inflammation, fever, redness Define immune system -- body's defence against infection by invading pathogens. Physical vs chemica...
How vaccines work- **Vaccines teach the immune system how to recognize and remember the pathogen and fight off specific disease-causing germs**. Signs of infection -- inflammation, fever, redness Define immune system -- body's defence against infection by invading pathogens. Physical vs chemical barriers First line of defence has chemical and physical barriers. **Physical Barriers** 1. **Skin**: Acts as a tough barrier to prevent pathogens from entering the body. 2. **Mucous Membranes**: Line the respiratory, digestive, and urogenital tracts, trapping pathogens. 3. **Cilia**: Hair-like structures in the respiratory tract that move mucus and trapped particles out of the lungs. **Chemical Barriers** 1. **Stomach Acid**: Destroys pathogens that are ingested with food. 2. Tears and Saliva: Help wash away pathogens from the eyes and mouth. 3. **Urine Flow**: Flushes out pathogens from the urinary tract. 4. **Lysozyme**: An enzyme found in tears, saliva, and other secretions that breaks down bacterial cell walls. 5. **Sebum**: An oily substance produced by the skin that has antimicrobial properties. 6. **Mucus**: Contains antimicrobial peptides and enzymes that trap and neutralize pathogens. 7. **Acidic pH of Skin**: Creates an environment that is inhospitable to many pathogens. 5. Compare Vaccination vs not vaccination A vaccinated person has memory cells with antibodies ready to fight invading pathogens so they won't get so sick while the body is producing more antibodies. However, non-vaccinated person won't have antibodies in the system to start fighting when pathogens invade the body. This could make the non-vaccinated person really sick while their body is making antibodies from scratch.
