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External barriers (non specific resistance)
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Defends against invasion of pathogens
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Pathogens
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Disease-producing agents that include infectious organisms, toxic chemicals and radiation
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Human environment for pathogens
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Human body harbors billions of bacteria because homeostasis provides ideal temperature, moisture and PH nutrients for microbial life
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___________ and ____________ are first line of defense against pathogens
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Skin and mucous membranes
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Skin=
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Too dry and nutrient weak for microbes to survive
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Epidermal cells and keratin
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Provide mechanical mechanical barriers against microbes
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Antimicrobial chemicals and lactic acid
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Come from sweat and form coating over skin
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Sebaceous glands
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Secrete sebum to form protective film over skin
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Mucous membranes
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Line body cavities that are exposed to the exterior, secretes mucous that traps microbes
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Areolar connective tissue
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Contains hyaluronic acid which gives it thick, sticky consistency which make it hard for microbes to penetrate them
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Lacrimal apparatus
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Secrete tears to prevent microbes from infecting eyeballs
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Saliva
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Dilutes the number of microorganisms and washes them from mouth and teeth
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Sweat glands
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Produce perspiration to flush microorganisms from the skin
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Mucous, tears, saliva, and perspiration contain:
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Lysozomes
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Lysozomes
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Dissolve bacterial walls
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