Flashcards in exam 2 Deck (92)
mutualism and commensalism
permanent association of two organisms that can't exist independently
both organisms benefit
one organism benefits the other is unharmed
live both a free living and a parasitic existence during their life cycles
completely dependent upon host for existence
what do ectoparasites cause?
infestation (flea, lice, etc. OUTside)
what do endoparasites cause?
infections (worms, INside)
host in which the sexual stage of the life cycle occurs
host in which the asexual stage of the life cycle occurs
animals other than man which harbor human parasites
what are the requirements for transmission of a parasitic infection?
source of infection, mode of transmission, the presence of a susceptible host
what are the functions of ectoplasm of protozoan?
excretion, movement, obtaining food/phagocytize, protection
what are the functions of the endoplasm of protozoan?
pseudopods (extension of ectoplasm)
what is a trophozoite?
(troph) the actively reproducing motile feeding stage (easily destroyed by unfavorable conditions, and can become a cyst in unfavorable conditions)
what is a cyst?
inactive, nonmotile, nonfeeding stage with protective cell wall (infective stage)
what is the most important parasitic amoeba?
where does Entamoeba histolytica live?
large intestines (colon)
describe the troph form of E. histolytica
exhibits progressive directional movement
contains one nucleus with a central karyosome
even-staining peripheral chromatin
may contain ingested RBC
describe the cyst form of E. histolytica
contains up to 4 nuclei and has cigar-shaped chromotoidal bars
what makes entamoeba gingivalis different from E. histolytica
gingivalis lives in the mouth and has no cyst stage
where does entamoeba coli live?
large intestine (colon)
describe the troph form of E. coli
exhibits sluggish random motility
contains one nucleus with an eccentric karyosome
uneven peripheral chromatin
contains ingested bacteria
describe the cyst form of E. coli
contains up to 8 nuclei
chromatoid bars (if present)
irregular with splintered cells
where does Endolimax nana live?
how is Endolimax nana recognized?
characteristic nuclear structure (has a large eccentric karyosome "lump of coal") seen in both the troph and cyst stages
cyst: can be ovoid
contains up to 4 nuclei
no chromatoidal bars