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41 Cards in this Set
- Front
- Back
Organisms that live on or in a second organism
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Parasites
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Parasites that play beneficial roles
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Normal flora
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Parasites that bring about damage or harm
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Pathogens
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OUtcome of the host-parasite relationship depends on?
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Pathogencity of parasite and resistance of host
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Growth of microorganisms in the host, does not always lead to injury
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infection
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Infections with no outward signs
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Subclinical infections
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Growth of microorganisms in the host, where host is harmed in some way
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Disease
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These are favorable environment for microbial growth due to they high amount of organic nutrients and growth factors
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Animal bodies
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When each region of the animal body differs chemically and physically from other regions
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Microenvironments
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These are almost always found on tissues exposed to outside world
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microbes
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Stages of infection
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Entry, colonization and growth, spread, Exit
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many microorganisms have surface structures that bind to receptors on animal cells this is called
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specific adherence
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Fimbriae, Glycocalyx, viral spikes and flagella are all examples of
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Microbe surface structures
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Generalized (systemic) infections are characterized by
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organisms pass through lymphatic vessels and are deposited in lymph nodes
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Prescence of bacteria in blood?
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Bacteremia
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Enzymes involved in invasion
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Hyaluronidase, Collagenase, and Streptokinase
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This enzyme is produced by streptococci and staphylococci and breaks down hyluronic acid (tissue cement)
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Hyaluronidase
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This enzyme is produced by clostridia that cause gas gangrene, it breaks down collagen network that support tissue
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Collagenase
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This enzyme is produced by streptococci and it breaks down fibrin clots formed by host in an effort to wall off microorganisms
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Streptokinase
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When organisms do not spread from site of infection this is know as a
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localized infections
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boils, carbuncles, or pimples are examples of
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localized infections
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Portals for exit of microorganisms from the body include:
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aerosols from respiratory system, fecal matter, vaginal discharge and semen, infected urine, blood, skin cells
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Proteins produced by some bacterial species and released extracellulary are
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Exotoxins
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These are highly toxic, highly specific as to "target cell" affected and can be fatal in small doses
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Exotoxins
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Neurotoxins affect
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Nervous system
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Botulinum Toxin is an example of an
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Exotoxin
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Enterotoxins affect
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Gastorintestine
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Nephrotoxins affect
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kidneys
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Two types of Hemolysins
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Phosphalipases and leukocidins
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These endotoxins attack cell membranes and cause cell lysis
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Hemolysins
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Phosphalipases ?
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attack phospholipids
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Leukocidins?
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lyze white blood cells, decrease host resistance
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These toxins are part of intergral process of cell
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endotoxins
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This toxin is contained in the LPS of outer cell wall, is released in large amounts only when cells lyse
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endotoxins
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Gas Gangrene, tetanus, botulism, diphtheria, and scarlet fever are representative diseases of
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Exotoxins
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Typhoid fever, urinary tract infections, and meningococcal meningitis are representative diseases of
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endotoxins
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Toxicity is much lower than exotoxins, but can cause death in very large doses
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Endotoxins
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The relative ability of a parasite to cause disease
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Virulence
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Determined by the invasiveness of the organism and its toxigenicity
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Virulence
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When pathogens are kept in culture for long periods, virulence is often decreased or completely lost
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Attenuation
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These strains can be used for vaccines
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Attenuated
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