develops more slowly immune response is enhanced by previous exposure adaptive

Develops more slowly immune response is enhanced by

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-develops more slowly -immune response is enhanced by previous exposure “adaptive” or “acquired” Concept 43.1 In innate immunity, recognition and response rely on traits common to groups of pathogens Innate Immunity of Vertebrates (Note: everything has an innate system) Barrier Defenses (External Innate Defense) -barrier defenses block the entry of many pathogens (protection at site of entry) - Epithelial cells are the barrier between the outside world’s contaminants and the body -cover the inner & outer linings of body cavities, such as the stomach and the urinary tract -these cells replicate often to replace damaged or dead cells -many layers provide better protection; the underlying tissue is still protected if one layer is lost - tight junctions are very difficult to alter and create a semi-permeable seal that few macromolecules or microbes can penetrate skin
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mucous membranes lining the digestive, respiratory, urinary, and reproductive tracts -produces mucus (fluid that traps pathogens and other particles) -ex) in trachea, ciliated epithelial cells sweep mucus and any trapped material upward prevent infection of lungs -Saliva, tears and mucous secretions that bathe exposed epithelia provide a washing action that also inhibits colonization by fungi and bacteria -body secretions can also create a hostile environment to pathogens -ex) lysozyme in secretions destroys the cell walls of susceptible bacteria -ex) acidic environment of the stomach kills most microbes -ex) secretion from oil & sweat glands makes skin acidic which prevents bacterial growth Cellular Innate Defenses ** Once barrier is breached, the pathogen will encounter cells & proteins of the internal innate immune system ** Q: What happens when the barrier is breached? A: The microorganism will be met by the cells/proteins of the innate immune system. These cells are “active” but some can be made more efficient at their jobs by interaction with the “specific” = “adaptive” immune system cells. -We want to make sure that we’re protected at the site of entry by immune cells/proteins -That location should be able to call for pre-made reinforcements (prepared but are not fully functional) -Proteins that are circulating in an inactive form can be quickly converted into active form Q: Why must we have preformed immune cells ready to protect us? A: Because a single bacterium with a doubling time of 1 hour can produce 20 million progenies in a single day. To combat this, we must have a rapid response. It is a lot faster to make a post-translational modification ( to activate proteins) than a pre-translational modification (making a protein to protect us). We don’t have time to call on for new gene transcription. So, it’s important that our immune cells are around and ready to fight immediately.
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  • Spring '19
  • RNA, Epithelial cells

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