chapter 14 Answers – Flashcards
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| symbiotic relationship |
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| relationship between 2 organism, often required due to nutritional needs 3 types: mutualism, commensalism, parasitism *relationships between organisms may change over time |
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| mutualism |
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| both members benefit from their interaction, some mutualistic relationships are required by one or both members while others are not required |
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| commensalism |
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| one member benefits whiteout significantly affecting the other |
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| parasitism |
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| the parasite derives benefit from its host while harming it, harm may range from slight to death |
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| which symbiotic relationship is often required by at least one of the organism? |
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| mutualism |
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| normal microbiota in hosts usually have symbiotic relationships ___________, but sometimes may be ________ |
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| usually commensalism others parasitic sometimes |
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| normal flora also known as |
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| indigenour microbiota microbes that colonize surfaces of body without normally causing disease |
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| which areas are colonized by microbiota |
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| the areas that normally come in contact with the external environment SKIN, EXTERNAL EAR, MOUTH, STOMACH |
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| resident microbiota |
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| part of the normal microbiota throughout life, most commensalism |
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| transient microbiota |
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| remain in the body for only a few hours/days/month before disappearing *dont persist because resident microbiota was initially established during your first months of life |
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| can normal microbiota become opportunistic pathogens? |
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| YES! - this happens when microbiota are found in unusual site of the body - OR immune system is suppressed -OR with changes in numbers or kinds of microbiota |
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| how can we be defensively compromised |
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| hiv, cancer, chemo, smoking, stress bad diet, lack of sleep |
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| under what 3 circumstances would normal microbiota be beneficial? |
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| 1. right number and kinds 2. right places 3. we are defensively competent |
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| establishment of a pathogen |
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| it must contaminate( or evade host, multiply) and then infect,(evade and damage host) and then cause disease |
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| infectious dose |
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| the minimum number of pathogens that must enter to cause infection |
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| infection implies whatdisease implies what? |
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| infection implies the pathogen can still increase in the host, disease implies that the host is being damages in some way |
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| at state of infection are we damaged? |
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| no not in any way |
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| damage due to pathogens is via |
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| 1. enzymes 2. toxins 3. antiphagocytic factors |
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| pathogenicity is a __________ |
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| PHENOTYPE! (means it has ability to make disease but not that it always will) |
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| 2 types of pathogens |
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| 1. opportunistic pathogen- has ability but needs opportunity (probably reduced immunity or opportunity needed) 2. true pathogen- can cause infection and disease no matter the state or health of host (DOES NOT MEAN IT IS MORE SEVERE) common cold and hiv are true pathogens |
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| examples of true pathogens |
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| common cold aids |
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| virulence |
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| what allows for pathogenisity but also describes the intensity to which they are a pathogen (all pathogen have virulence but the level varies) HIV has high virulence, common cold has low virulence |
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| hiv has high ____________ common cold has low _______ |
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| virulence |
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| what gives an organism virulence? |
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| virulence factors (more of your genotypic characteristic) (if flagella is present for purpose of causing infection, this is a virulence factor) (enzymes, toxins are also virulence factors) |
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| reservoirs of infectious disease of humans |
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| the site where the pathogens are maintained as a source of infection |
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| what are three types of reservoirs? |
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| 1. animal: -domesticated or wild -zoonases- diseases spread naturally from usual animal hosts to humans (lyme disease, ring worm, malaria, rabies) -direct contact with animals and their wastes, eating animals or via blood sucking arthropods 2. human 3. nonliving (soil, water, food) |
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| what are zoonases |
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| disease spread naturally from usual animal hosts to humans -rabies -lyme disease -ring worm -malaria *contract b=via animal contact or animal waste contact, eating animals, or via blood sucking arthropods |
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| human reservoirs may be ________ or ________ |
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| symptomatic (carriers) or asymptomatic |
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| 3 portals of entry for microbes |
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| 1. skin 2. micous membrane 2. placenta (for fetus) |
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| role of adhesion in infection |
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| - some cells can change the adhesion factors overtime helping the pathogen evade the immune system and allowing the pathogen to attack more than one kind of cell. |
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| viruses and bacteria sometimes have surface lipoprotein and glycoprotein molecules called ___________ that do what |
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| ligands enable them to bind to complementary receptors on host cells (ADHESION FACTOR) |
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| bacterial cells that have lost the ability to make ligands- whether as a result of some genetic change or exposure to some physical of chemical agents become __________ |
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| harmless or avirulent |
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| disease |
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| when injury from pathogen is significant enough to result in disfunction of the body any change from a state of health *disease is also known as morbidity |
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| signs vs symptoms |
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| signs- objective symptoms- what the patient feels (subjective) |
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| congenital vs hereditary disease |
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| hereditary- genetically transmitted from parents to offspring congenital diseases- present at birth, regardless of the cause (could be hereditary environmental or infectious) |
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| study of the cause of disease |
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| etiology |
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| extracellular enzymes (virulence factor) 3 types |
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| -pathogens secrete enzymes which enable them to dissolve structural chemicals in the body and thereby maintaing infection -hyalaronidase and collagenase degrade molecules to enable bacteria to invade deeper tissues |
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| hyalaronidase |
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| extracellular enzyme virulence factor digests hyaluronic acid or "glue" holding animal cells together |
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| collagenase and mucinase |
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| extracellular enzyme virulence factor breaks down collagen micinase- breaks down mucus lining intestinal tract |
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| kinases |
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| extra cellular enzyme virulence factor staphylokinase and streptokinase - digest blood clots allowing subsequent invasion into damaged tissues |
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| Toxins (virulence factor) 2 tpyes |
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| toxins- harm or trigger host immune response causing damage toxemia- toxins enter bloodstream 2 types: ENDOTOXIN AND EXOTOXIN ENDOtoxin- central to their pathogenicity in that they destroy host cells or interfere with host metabolism - cytotoxins: kill host cells in general affect their function -neurotoxind- specificallyy interfere with nerve cell -enterotoxins- affect cells lining the GI tract ENDOTOXIN- gram negative bateria release lipid A or endotoxin which is part of the outer wall membrane when they die causing fever, inflammation, shock, bleeding, diarrhea, blood coagulation |
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| antiphagocytic factors include |
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| - to limit the extent and duration of infections, the bodes phagocytic cells such as WBCS called macrophages engulf and remove invading pathogens ANTIPHAGOCYTIC FACTORS INCLUDE 1. CAPSULES! are effective virulence factors because many capsules are composed of chemicals normally found in the body, as a result they do not trigger immune response and therefore phagocytes don't come. Capsules are also slippery stopping phagocytes. |
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| some bacteria produce chemicals that prevent the fusion of lysosomes with phagocytic vehicles, so the bacteria ____________ |
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| bacteria survives in the vesicle |
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| leukocidins |
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| chemicals capable of destroying phagocytic white blood cells outright |
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| incubation period |
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| the time between infection occurrence and the first symptoms or signs of disease. - length depends on virulence of the infective agent, the initial number of pathogens, state and health of patient, nature of pathogen and reproduction time, and site of infection, |
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| prodromal period |
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| - a short time of generalized, mild symptoms that precedes illness - not all have this stage |
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| illness period |
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| - the most severe starve of an infectious disease - has not gotten too bad yet -usually when physician sees patient |
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| decline period |
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| - body gradually returns to normal -symptoms subside - immune products peak - if patient doesn't recover, disease is fatal |
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| convalescence |
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| patient recovers from illness, tissues repaired, returns to normal. |
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| portals of exit for pathogens |
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| - earwax, tears, nasal secretions, saliva, sputum, respiratory droplets, blood, vaginal secretions, semen, milk, excreted bodily wastes |
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| modes of infectious disease transmission |
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| 1. contact transmission: direct contact, indirect contact(spread by fomites or inanimate objects that are inadvertently used to transfer to host), droplet 2. vehicle transmission: airborne, waterborne, foodborne, bodily fluids 3. vector transmission: biological, mechanical |
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| airborne transmission is what mode aerosol? |
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| contact transmisison (droplet) involves the spread of pathogens father than one meter to the respiratory mucous membranes of a new host via an aerosol or cloud of small droplets and solid particles suspended in air. aerosols can contain pathogens in dust or droplets |
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| aerosols come from |
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| sneezing coughing, air conditioning, sweeping, mopping, changing clothes or bed linens, or from flaming inoculation loops |
