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71 Cards in this Set
- Front
- Back
symbiosis |
-a relationship in which two organisms live together |
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commensalism |
-type of symbiosis -one organism benefits and the other remains unharmed |
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parasitism |
-type of symbiosis -one organism benefits (parasite) and other is harmed (host) |
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mutualism |
-type of symbiosis -both organisms benefit |
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neutralism |
-type of symbiosis -neither organism benefits |
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colonization |
-condition in which presence, growth, and multiplication of microorganism on or in host have no clinical effect and no detectable immune response |
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infection |
-condition in which presence, growth, and multiplication of microorganism on or in the host elicit some form of response, either clinical or immunological |
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sub-clinical infection |
-immune response developed without overt signs or symptoms |
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normal flora |
-organisms that normally populate a body site without causing disease -generally commensalistic or mutualistic relationships -remain for life but change in response to internal environmental alterations |
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disease |
-disorder recognizable by a specific set of signs and symptoms |
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virulence |
-power of an organism to cause disease -depends on toxigenicity and dose |
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invasiveness |
-ability to penetrate and overcome host defenses |
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toxigenicity |
-ability to produce toxins |
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dose |
-number of organisms required to start the disease process |
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pathogenicity |
-organism's ability to cause disease |
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obligate pathogens |
-pathogens that will always cause disease (usually parasites) |
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non-pathogens |
-organisms that under normal conditions will not cause disease |
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opportunistic pathogens |
-organisms that may be normal flora under usual circumstances but may become pathogens if conditions change |
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immunosuppression |
-specific administration of a drug therapy or disease state that interferes with immune mechanism, either humoral or cellular |
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immunocompromised |
-person born with immune system defect, either humoral or cellular |
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endogenous infections |
-infections caused by organisms from within patient's own normal flora |
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exogenous infections |
-infections caused by organisms from external sources |
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nosocomial infections |
-infections acquired during hospital stay |
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community-acquired infections |
-infections that spread naturally through the community external to the hospital |
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communicable diseases |
-diseases capable of being transmitted from one host to another |
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contagious |
-diseases that spread with considerable ease |
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non-communicable diseases |
-diseases acquired directly from the environment and cannot be transferred easily from one host to another (eg. tetanus) |
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endemic diseases
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-diseases indigenous within a given geographic area
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epidemic
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-explosive outbreak within a population |
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pandemic |
-worldwide outbreak of a disease |
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acute diseases |
-diseases that develop rapidly, present with severe symptoms, climax and fade quickly |
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chronic diseases
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-diseases that develop slowly, symptoms develop slowly and are sometimes vague, rarely reach climax and take months for convalescence, sometimes never really fading away |
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primary disease |
-disease that occurs in a previously healthy body |
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secondary disease
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-disease that develops in an already diseased body |
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systemic infection |
-infection that has spread throughout body to many or all organs |
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local infection |
-infection restricted to a single area of the body |
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direct transmission |
-when a disease travels from person to person
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vectors |
-animate objects that transmit disease |
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fomites |
-inanimate objects that transmit disease |
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congenital
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-transfer of disease directly to fetus in-utero or as child passes through birth canal |
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air-borne transmission
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-indirect mode of transmission that occurs when disease-causing organisms are inhaled
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direct contact
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-if disease is transmitted to new host through contact with infected individual or source |
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indirect contact
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-occurs if source of infection is food, water, or fomites or if disease is transmitted to new host via living organisms (eg. ticks or fleas) |
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zoonoses |
-human diseases caused by organisms that are primarily animal pathogens and accidentally are transmitted to humans |
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reservoir |
-the source of a disease, necessary for disease to perpetuate itself |
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carrier |
-special type of reservoir in which a person who has recovered from the disease continues to spread infectious organisms |
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clinical disease
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-when conditions occur to an extent that the patient exhibits clinical-symptoms
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subclinical disease |
-when few or no obvious symptoms occur |
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What are the 5 stages of the disease process?
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-period of incubation -prodromal period -acme period -period of decline -convalescence |
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period of incubation
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-time between entry of organism into host and the appearance of symptoms |
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prodromal period |
-great competition between host and invading organism |
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acme period |
-display of specific symptoms of the disease |
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period of decline |
-period directly before recovery, considered to be a crisis time, during which excessive amounts of heat are released by sweating |
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convalescence |
-when body systems return to their normal state |
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What factors are important to the length of the incubation period?
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-organism's generation time -organism's invasiveness and its toxicity -portal of entry -level of resistance in host |
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List some of the body's non-specific body defenses?
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-mucous membranes -stomach acidity -vaginal acidity -bile -duodenal enzymes -lysozyme -interferons -phagocytes, alveolar macrophages, Kupfer cells |
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inflammation
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-dilation of blood vessels which leads to increase in capillary permeability and in phagocytic activity at site of infection |
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pus |
-produced by increase in phagocytic activity during inflammation |
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purulent |
-term describing a specimen full of pus |
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boil/abscess
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-occurs when purulence is enclosed in a wall of fibrin and clotting process is activated |
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carbuncle |
-collection of several abscesses |
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fever
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-body temperature above normal body temperature, due to the effect of bacteria, viruses and other foreign organisms on the hypothalamus |
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humoral immunity
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-specific body defense resulting in production of antibodies to antigens |
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cell-mediated immunity
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-particularly involved in infections caused by parasites, viruses, rickettsia, and bacteria that are intracellular parasites |
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infective dose
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-number of organisms that must enter body in order to establish the disease -immunity occurs if exposure dose is less than infective dose |
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invasiveness |
-the ability of an organism to penetrate tissues and cause structural damage
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Which enzymes produced by bacteria affect their toxigenicity? |
-coagulase -streptokinase -hyaluronidase -leukocidin -hemolysin |
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endotoxins
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-toxins that are part of cell wall of Gram negative organisms and are released upon the death of the cell |
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exotoxins
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-predominantly produced by Gram positive organisms |
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By which mechanisms do bacteria overcome host defenses?
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-retrieval of nutrients from host -inhibition of phagocytosis -evasion of immune response -damage to host tissues -indirect damage to host tissues through an immune reaction |
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