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35 Cards in this Set
- Front
- Back
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what are the two broad categories of medical parasites?
what's the difference? |
-protozoa - one-celled
-metazoa - many-celled |
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what are the three phyla of metazoa?
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-platyhelminthes
-aschelminthes -arthropoda |
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what are the two classes of platyhelminthes?
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-trematoda
-cestoda |
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what are trematoda?
cestoda? |
flukes
tapeworms |
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what is the class of aschelminthes?
what is the common name? |
class nematoda
roundworms |
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what are the four classes of arthropoda?
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-crustacea
-chilopoda -arachnida -insecta |
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what are the two ways to identify parasites in lab?
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-morphologically
-immunologically |
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what type of processing is done for intestinal parasites?
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O and P
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what does O and P stand for?
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ova and parasites
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what are two points that need consideration re: parasite specimens?
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-freshness
-number of specimens |
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how fresh of a spec will give motile trophozoites?
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within 30 min.
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what are the time limits that mandate how you handle a specimen?
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-within under 3 hrs handle it as fresh.
-if over 3 hrs old, preserve it. |
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what are 4 requirements of a fecal specimen's collection?
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-if barium was given, wait 5 days before collecting feces.
-no urine - acidity distorts the parasite. -direct into dry, clean container. |
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what is the preferable number of specimens for parasite testing?
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2-3:
1 every other day 1 after a laxative that's in a perfect world |
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how many specimen are required for entomoeba histolytica?
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6
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what's the first thing done on a fresh or preserved specimen for o and p?
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DIRECT EXAM
-macro -micro |
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4 things you look for when doing a macroscopic direct exam of a stool:
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1. Color - blood?
2. Consistency - loose or well-formed = cyst or trophoz. 3. Interfering substances (Ba) 4. Adult Parasites |
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What two solutions are used in a microscopic direct test?
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-lugol's iodine
-saline |
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at what powers do you do the micro direct test?
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-first low - for big parasites
-then highdry - for small -Always do both!! |
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what are 2 things that can be used for preservation?
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-PVA (polyvinyl alcohol)
-10% Formalin |
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what are the advantages of PVA?
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-can do permanent stains on it later
-good for liquidy stools |
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what is formalin good for?
what's bad about it? |
-all stool forms except liquidy.
-can do a concentration proced Disadv: can't do a trichome permanent stain. |
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why do a concentration method?
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to increase chances of finding parasite - can be hard on the direct test.
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what are two types of conc. methods?
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-zinc sulfate flotation
-formalin ethyl acetate sedimentation |
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Regarding the zinc sulfate flotation procdure, what's the
-advantage -2 disadvantages? |
Adv: fecal debris is seperate at the bottom of tube.
Dis: 1. if the thing being sought is a large egg, it doesn't float. 2. Can only be done on fresh specimen. |
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What's the biggest disadvantage of the form. ethyl acetate sedimentation?
-Advantage? |
Dis: fecal debris is on slide.
Adv: can see ALL parasites and can use formalin-preserved specimens. |
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what are 4 characteristics of the class Nematoda?
-what is the common name? |
1. Shape
2. Cuticle 3. Digestive Tract. 4. Reproductive System -common name is Roundworm |
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What shape are roundworms?
what is their protective, thin covering called? |
round, bilaterally symmetrical, tapered at one end.
-cuticle |
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what is the digest. tract like of roundworms?
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well developed, with a
-buccal cavity -esophagus -intestine |
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what is the reproductive system of nematodes like?
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Sexes are seperate and do not multiply in man.
1 ovum gives 1 adult. Females are bigger than males. |
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What are the four Phyla of the Protozoa?
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-Sarcomastigophora
-Ciliophora -Apicomplexa -Microspora |
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What 2 subphyla are within Phylum Sarcomastigophora?
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-Sarcodina (amoeba)
-Mastigophora (flagellates) |
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What is in Phylum Ciliphora?
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Balantidium coli
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What 2 subphyla are within Phylum Apicomplexa?
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-Coccidia
-Sporozoa |
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What is in Subphylum Microspora?
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Not a whole lot worth mentioning
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