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20 Cards in this Set
- Front
- Back
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What are the criteria for symbiosis or symbiotic association?
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The net outcome is neutral, harmful or beneficial
Association can be fleeting or obligate There may be a physiologically dependency: the extent to which 1 organism needs another |
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How many subgroups of symbiotic groups are there?
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4
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Do these subgroups display features that differ in functional and measurable terms?
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Yes
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What are the 4 subgroups?
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1) Phoresis
2) Commensalism 3) Parasitism 4) Mutualism |
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What kind of a host do each of these subgroups have?
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Phoresis: Phorant host
Commensalism: Commensal host Parasitism: Parasite host Mutualism: no host, mutuals together |
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What kind of contact exists in phoresis?
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Chance contact
-->Organisms share the same ecological niche --> NO physiological relationship/dependency exists |
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What is the net effect of phoresis on the host?
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Neutral, nothing happens to the host
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What are generally the hosts in pohoresis?
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House flies etc
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What do theses hosts act as?
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Mechanical vectors/carriers for phorants (viral, bacterial and protozoan) that are carried from point A to point B (exposed human excrement to exposed human food)
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What do these flies end up causing?
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Food borne diseases
Ex: Polio, Salmonella, Shigella, Vibro sp. (also water-borne) |
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What is the ineffective stage?
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Protozoan cyst
-From pt A to pt B --> Giardia, Entamoeba histolytica, Cryptosporidium sp |
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What is commensalism?
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Facultative:: No survival risk for commensal
Obligate: Required for the commensal to survive |
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What is the net effect of commensalism?
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One sided benefit
->Flows towards the commensal -->Host is neither harmed/benefited |
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What are some examples of commensals?
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Entamoeba coli (Resides in the biotic zone-mucous layer in the large bowel)
-Has 2 stages Trophozoite and cystic E. gingivalis (gum) Pin worm (cecum) |
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What is involved in parasitism?
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Host and parasite
Parasite is smaller than host |
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What effect does the parasite have on the host?
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Usually causes injury (can be direct or indirect tissue injury)
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What are the mechanisms that determine the pathologic effects of the parasitic disease? (6)
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1) Host's nutritional status
2) Repeated exposure 3) Prompt tissue injury 4) Release of parasite derived toxins/hydrolytic enzymes 5) Mechanical (blockage/obstruction and P atrophy) 6) Delayed tissue injury |
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How does the host's nutritional status affect the pathology of the disease?
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If there's a large parasite burden, the clinical course may be exacerbated in malnourished children
Ex: hook worm, ascaris, diphyllobothrium latum, |
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How does repeated exposure to parasitic infection affect the pathology of the disease?
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-Get high level of sensitization
-->Too much inflammationn and granuloma formation around eggs and migrating larvae that are trapped in soft tissues, causing extensive fibrosis and organ dysfct |
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http://www.mcgill.ca/files/microimm/03_Ali-Khan_2010.pdf
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http://www.mcgill.ca/files/microimm/03_Ali-Khan_2010.pdf
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