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Morphology and Life cycle
Members of the class nematoda assume 3 basic morphologic form, namely:
1.
2.
3.
*Remember life cycle depends upon the species of nematode.*
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What life stage is it when sexes (reproductive system) separate and the worm is now equipped with digestive system.
Adult worm
Review point : Nematodes are the only helminth with complete digestive system: mouth, esophagus, midgut and anus.
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Organism that contain the reproductive adult stage of nematodes are known as the _________.
final or definitive host
*To review on the kinds of parasite,host and vector you can visit flashcard 31416 or 361417.*
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Organism that are required for the completion of the nematode life cycle but do not contain final reproductive adult stage are known as the ______ host.
intermediate
*To review on the kinds of parasite,host and vector you can visit flashcard 31416 or 361417.*
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Any idea about molting or ecdysis (pronounced as ek·duh·suhs)?
How many molts do nematodes undergo?
MOULTING in nematodes can be separated into two distinct processes: the deposition of the new cuticle and ecdysis, or the shedding of the old.
They usually undergo 4 molts
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What are the 3 larval types?
- 1.rhabditiform
- 2.filariform
- 3.microfilaria
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The larval type in which
it is the L1 & L2 of many parasitic species. Esophagus joined to terminal bulb by narrow isthmus.
Rhabditiform
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The larval type in which
it is the L3 of many species
esophagus elongate without distinct posterior bulb;isthmus is absent
filariform
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The larval type in which
it is the immature L1 of filarids
embryo, with body covered by flattened epidermal cells and no guts
microfilaria
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What is the typical life cycle of intestinal nematodes.
- 1.The worm develops in the intestine.
- 2.Eggs are released with feces into the environment.
- 3.Larvae hatch and develop in the environment
- 4.Infection occurs through skin penetration by larvae.
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It is the only larvae stage that occurs after skin penetration in intestinal nematodes.
L4 and then it develops into an adult.
(eggs out with feces - they hatch in the soil (environment),L1,L2, L3, skin penetration and then L4,until it develops into an adult)
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One can be infected by filariae by what type of vector?
blood-sucking insects such as mosquito
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What stage in the parasitic life cycle of a nematode can you incorporate a vector?
L1, can either be in the environment or microfilariae in blood-ingested arthropods.
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Usually ______ is bigger than _______.
Female is bigger than male nematode.
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Inserted in the female's vulva to attach the male to the female and to widen the vulva against the inner body pressure for sperm transfer.
Copulatory spicules in male nematodes
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How many testes does a male nematode have?
Usually two, sometimes one.
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How many ovaries does a female nematodes has?
mostly two, few with other numbers.
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