Phylum Nematoda

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Phylum Nematoda

• The Roundworms

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General Characteristics
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3 germ layers and a false body cavity
mesoderm
pseudocoelom
ectoderm
digestive tube
endoderm
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bodies are round with tapered ends
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Anterior End
mouth
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Posterior End
some have a spicule
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sexes are separate
females
males
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most are free-living
Some are parasites
roundworm in foot
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some form cysts when conditions are harsh
cyst larvae
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adult
larva
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Ascaris
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males are smaller and have hooks
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Dog Ascaris
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Ascaris eggs
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Ascaris in human intestine
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Trichinella
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Trichinella is contracted from undercooked pork.
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The head of Trichinella.
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Trichinella
sexes are separate
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Trichinella invades muscle tissue and forms cysts.
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Hookworms
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anterior end with hooks
You can get these by kissing your cat, or
walking barefoot on infected soil!!
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scolex with hooks
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Hookworm eggs from stool
egg
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Pinworms
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Pinworms - most common parasite in children
small pin-like bodies
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egg
Pinworm egg
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Heartworms
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Heartworms in dog heart
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The End