nonspecific-1 - 1 HOST DEFENSES(RESISTANCE A Resistance...

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1 HOST DEFENSES (RESISTANCE) A. Resistance - ability to ward off infectious diseases B. Susceptibility - lack of resistance C. Two types host defenses (resistance) 1. Nonspecific resistance a. Effective against wide variety organisms b. Due to anatomical and physiological characteristics of host 2. Specific resistance (immunity) a. Effective against only one microbe b. Must be acquired following exposure to microbe NONSPECIFIC RESISTANCE A. Categories of nonspecific resistance 1. Natural (inherited) resistance 2. Mechanical - Chemical barriers 3. Cellular defenses 4. Inflammation 5. Fever B. Natural (innate, inherited) resistance - (genetic) inherited factors 1. Species resistance 2. Racial resistance 3. Individual resistance C. Mechanical - Chemical barriers 1. Skin a. Intact, unbroken - mechanical covering b. Multilayered structure (stratified squamous epithelium) c. Keratinized cells - hardened, protective barrier d. Sebaceous (oil) glands sebum (oil) fatty acids acid pH (4.0-5.0) e. Sweat glands secrete perspiration - NaCl, enzymes (lysozymes)
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2 2. Mucus membranes (m.m.) a. Multilayered structure b. Coated with protective layer mucus - cleanses surface, removes microbes. c. Mucus contains enzymes, may be acid, etc. d. In RT m.m. are ciliated 1). Traps microbes 2). Beating action movement mucus mucociliary escalator (Ex.: lining bronchi) 3. Eyes a. Eye lids, eye lashes - mechanical protection b. Conjunctiva - m.m., coated with mucus c. Tear glands - secrete tears 1). Mechanical washing action. 2). Contain NaCl, concentrations lysozymes - lysis cell walls (murein) 4. Ears a. Auditory canal lined with ciliated epithelium b. Ceruminous glands 1). Secrete cerumin (wax) 2). Traps microorganisms - moves out away from middle ear due to beating action cilia c. Eardrum - mechanical barrier 5. Digestive tract a. Lined with m.m., coated with mucus b. Oral cavity - saliva contains digestive enzymes c. Stomach - HCl, enzymes, bile salts
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nonspecific-1 - 1 HOST DEFENSES(RESISTANCE A Resistance...

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