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26 Cards in this Set
- Front
- Back
What are the four main physical barriers?
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Skin
URT LRT GI Tract |
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What is skin composed of?
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epidermis (keratin)
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Why is the skin a good barrier (4 reasons)?
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low moisture
high salt sebaceous glands secrete fatty and lactic acids which decrease pH antimicrobial peptides expressed in sweat glands (ie Dermcidin) |
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How many bacteria is URT exposed to in a typical day?
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>1000
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What are the major barriers within the URT?
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mucocilliary system
antimicrobial peptides in body secretions normal flora |
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What is the function of mucous? Of cilia?
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mucous traps, cilia sweeps
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Give an example of an opportunistic pathogen in URT
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Neisseria meningitidis
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What is the URT?
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The nose, throat, and ears
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What is the LRT?
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trachea, bronchial tubes, alveoli in lungs
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What are the three LRT defence mechanisms?
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mucocilliary system
macrophages and antibodies in lungs antimicrobial proteins and peptides |
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What antimicrobial peptides are present in LRT? Proteins?
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Peptides: defensins, LL-37
Proteins: lactoferrin, lysozyme |
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What part of the body contains the majority of normal flora?
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GI tract
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What are the three GI tract defenses?
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stomach acidity
peristaltic movements (expels potential colonizers) microbial antagonism from normal flora |
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What are the main antimicrobial substances?
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lysozyme
lactoferrin lactoperoxidase antimicrobial peptides (beta-defensins, LL-37) |
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What does lactoferrin?
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binds iron
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What do enzymes such as lacteroperoxidase do?
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generate singlet oxygen to kill bacteria
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Where are antimicrobials found?
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tears, saliva, lymph, mucus, blood
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How does inflammation help against bacterial infections?
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limits spread
recruits phagocytes enhances phagocytosis repairs tissue damage |
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___ bind to ___ in blood and ___ cells in tissue resulting in histamine release
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anaphylatoxins
basophils mast cells |
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What does the release of histamine cause?
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vasodilation
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What is the function of fibrinogen in acute inflammation?
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forms a fibrin clot around damages host cells localizing the infection
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What process is responsible for fever in chronic inflammation?
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production of cytokines
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How do activated/inflammatory macrophages damage tissue?
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secrete toxic oxygen intermediates, and tissue-damaging enzymes
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Why is chronic inflammation bad?
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extensive tissue damage, fever
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What bacteria causes the chronic infections: gastritis, gastric ulcers, and gastric cancers?
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Helicobacter pylori
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How are peptic ulcers perpetuated?
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Bacteria lives in mucous layer lining, secreteing urease to nutralize stomach acid and protect itself. Chronic inflammation destroys stomach lining, which allows HCl access to deeper tissues.
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