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35 Cards in this Set

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what are the two broad categories of medical parasites?

what's the difference?
-protozoa - one-celled
-metazoa - many-celled
what are the three phyla of metazoa?
-platyhelminthes
-aschelminthes
-arthropoda
what are the two classes of platyhelminthes?
-trematoda
-cestoda
what are trematoda?
cestoda?
flukes
tapeworms
what is the class of aschelminthes?
what is the common name?
class nematoda

roundworms
what are the four classes of arthropoda?
-crustacea
-chilopoda
-arachnida
-insecta
what are the two ways to identify parasites in lab?
-morphologically
-immunologically
what type of processing is done for intestinal parasites?
O and P
what does O and P stand for?
ova and parasites
what are two points that need consideration re: parasite specimens?
-freshness

-number of specimens
how fresh of a spec will give motile trophozoites?
within 30 min.
what are the time limits that mandate how you handle a specimen?
-within under 3 hrs handle it as fresh.

-if over 3 hrs old, preserve it.
what are 4 requirements of a fecal specimen's collection?
-if barium was given, wait 5 days before collecting feces.
-no urine - acidity distorts the parasite.
-direct into dry, clean container.
what is the preferable number of specimens for parasite testing?
2-3:
1 every other day
1 after a laxative

that's in a perfect world
how many specimen are required for entomoeba histolytica?
6
what's the first thing done on a fresh or preserved specimen for o and p?
DIRECT EXAM
-macro
-micro
4 things you look for when doing a macroscopic direct exam of a stool:
1. Color - blood?
2. Consistency - loose or well-formed = cyst or trophoz.
3. Interfering substances (Ba)
4. Adult Parasites
What two solutions are used in a microscopic direct test?
-lugol's iodine
-saline
at what powers do you do the micro direct test?
-first low - for big parasites
-then highdry - for small

-Always do both!!
what are 2 things that can be used for preservation?
-PVA (polyvinyl alcohol)

-10% Formalin
what are the advantages of PVA?
-can do permanent stains on it later
-good for liquidy stools
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.
why do a concentration method?
to increase chances of finding parasite - can be hard on the direct test.
what are two types of conc. methods?
-zinc sulfate flotation

-formalin ethyl acetate sedimentation
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.
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.
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
What shape are roundworms?

what is their protective, thin covering called?
round, bilaterally symmetrical, tapered at one end.

-cuticle
what is the digest. tract like of roundworms?
well developed, with a
-buccal cavity
-esophagus
-intestine
what is the reproductive system of nematodes like?
Sexes are seperate and do not multiply in man.

1 ovum gives 1 adult.
Females are bigger than males.
What are the four Phyla of the Protozoa?
-Sarcomastigophora
-Ciliophora
-Apicomplexa
-Microspora
What 2 subphyla are within Phylum Sarcomastigophora?
-Sarcodina (amoeba)
-Mastigophora (flagellates)
What is in Phylum Ciliphora?
Balantidium coli
What 2 subphyla are within Phylum Apicomplexa?
-Coccidia
-Sporozoa
What is in Subphylum Microspora?
Not a whole lot worth mentioning