350 lecture pt 2

350 lecture pt 2 - Lecture 8 1 Describe the different types...

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Lecture 8 1. Describe the different types of relationships between humans and microorganisms: a. Symbiosis: benefits host, doesn’t harm organism, only provides a place to live b. Mutualism: benefits both host and organism c. Commensalism: no harm to host, and only benefits organism d. Pathogenicity: harms host, and benefits organism e. Opportunism: normally benign foreign organisms become pathogenic 2. What are the stages of infection? a. Colonization: a population of organisms growing in place. b. Invasion: pathogen resist defenses and goes beyond initial colonization c. Multiplication: cells grow and use our resources d. Spread: spread to other areas 3. What are the consequences of each stage of infection? a. Colonization: Source of cross infection to others b. Invasion: opportunity for cell injury, alterations in function, or cell death c. Multiplication: tissue damage, cell alterations, or cell death and disease symptoms d. Spread: Local or systemic manifestations of disease through cell injury or effect of toxins. 4. Know the definitions of: a. Mechanism of action: direct damage of cells, interference with cellular metabolism, and disrupting cell functioning due to toxin production b. Infectivity: ability of the pathogen to invade and multiply in the host c. Pathogenicity: ability of the agent to produce disease, this depends on the speed of pathogen reproduction, production of toxins and extent of tissue damage. d. Virulence: potency of a pathogen measured in terms of the number of microorganisms or toxin required to kill a host. e. Immunogenicity: ability of pathogens to induce and immune response. f. Toxigenicity: a factor important in determining a pathogen’s degree of virulence, ability to produce toxins g. Portal of entry: route by which a pathogen infects the host, form of contact, the spread is facilitated by the ability of pathogens to spread through lymph and blood where they multiply and cause disease. 5. What host defense mechanisms protect us against infection? a. External barriers: biochemicals, and cells with specific receptors b. Inflammaition: phagocytes, natural killer cells and complement c. Adaptive immunity: t and b cells 6. Describe some mechanisms of bacterial virulence: a. Thick capsules of carbohydrates or proteins that prohibit phagocytosis or antibody identification b. Some proteins that are able to suppress compleent c. Rapid proliferation rates: will grow so fast they surpass immune system d. Exotoxins: these are proteins that are released during growth, oftentimes have specific actions and will damage membranes or activated second messengers. e. Endotoxins: Lipopolysaccharide in the wall og gram negative bacteria, which release with lysis, bacterial growth or antibiotic use, and activate inflammatory response 7. What are the physiological effects of bacterial lipopolysaccharide? a.
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This note was uploaded on 04/22/2008 for the course NURS 350 taught by Professor Montgomery during the Spring '08 term at Arizona.

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350 lecture pt 2 - Lecture 8 1 Describe the different types...

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