1 phylum platyhelminthes. flatworms are simple bilateral animals. flatworms have a solid body and...
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Phylum Platyhelminthes
Flatworms are simple bilateral animals. • Flatworms have a solid body and incomplete or absent gut.
• There are three classes of flatworms.
– planarians
head
pharynx
mouth
sucker
eyespot reproductivesystem
gut cavity
• Flukes
– Tapeworms
CHARACTERISITCS OF ALL WORMS
InvertebrateElongated bodies
Bilateral symmetryCephalization
Cerebral ganglia “brain”No respiratory organs
(Breathe through skin)
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FLATWORMSPHYLUM: Platyhelminthes
FREE LIVING PARASITIC
Planaria Flukes & Tapeworms
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Phylum Platyhelminthes
• Flat worms• Acoelomate• Bilateral symmetry• Hermaphroditic
– Monoecious
• One opening for digestive system
• Paired lateral nerve cords & cerebral ganlion
• Flame cells
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Class Turbellaria
• Eye spots
• Ciliated surface
• Regenerate if cut in two
• Most are free-living
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Phylum Platyhelminthes: Class Turbellaria
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Acoelomate
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Turbellaria
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Nervous System
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BrainBrain
AuricleAuricle
Cerebral Cerebral ganglionganglion
PairedPairednerve cordsnerve cords
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Excretory System
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Class Trematoda
• Flukes• Parasites• Holdfast devices
– Most• Complex life cycle• Intermediate host
– Animal with juvenile stage• Definitive host
– Animal with adult stage
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Clonorchis sinensis
• Chinese liver fluke• 50 million people• Cirrhosis of liver• Diarrhea• Edema• Pain
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Clonorchis sinensis
Oral sucker
Intestine
Uterus
Yolk gland
Testes
Ovary
Seminal recepticle
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Fascioloa hepatica
• Sheep liver fluke• Sheep, cattle and
man– Weight loss
• Eat vegetation with metacercaria
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Life Cycle of the Sheep Liver Fluke
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Fasciolopsis buski
• Intestinal fluke• 10 million people• Man and pigs• Hemorrhage and
abscesses of small intestine
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Paragonimus westermani
• Lung fluke• Carnivores, pigs,
rodents and man• May be fatal
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Schistosoma
• Blood flukes• 200 million people• 1 million deaths/year
PARASITIC FLATWORMSchistosoma
Worms can block blood vessels to organs causing irritation, bleeding, tissue decay producing disease called = SCHISTOSOMIASIS
NOT IN USA but infects over 250 million people worldwide
http://www.coc.org/focus/food/pics/rice_paddy.jpg30
HUMAN BLOOD FLUKESchistosoma
Larva hatches from
egg & infects snail(intermediate host)
Eggs leave body in urine or feces
Adult worms mature & reproduce in blood vessels; eggs travel to intestines or bladder
Larvae grow tails and leave snail
Immature worms burrow through skininto blood vessels
http://www.biosci.ohio-state.edu/~parasite/lifecycles/schistosoma_lifecycle.gif
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Schistosome
• Cercaria have forked tail
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Swimmers Itch
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Class Monogenea
• One host• Ectoparasites
– Mainly fish• Opisthaptor
– Attachment to host
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Class Cestoidea
• Tape worms• No digestive system• 40 feet long
TAPEWORMS
PARASITIC FLATWORM that lives in HOST animal intestines
Dog tapeworm
http://www.bangkokhealth.com/cimages/tapeworm02.jpg
http://www.biosci.ohio-state.edu/~parasite/pictures/whole_tapeworms.GIF
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SCOLEX - Head with suckers and hooks to help hold on inside host
http://www.nicksnowden.net/images/Taenia_scolex_drawing.gif
ScolexScolex
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• PROGLOTTIDS hermaphroditic reproductive structures
• (contain both male & female sex organs)
Containfertilized eggs
Shed in feces
http://www.biosci.ohio-state.edu/~parasite/labeled_taenia.html
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Proglottid
UterusUterus
TestesTestes
OvaryOvary
Yolk glandYolk gland
Vas deferensVas deferens
Seminal receptacleSeminal receptacle
• TEGUMENT• Thickened PROTECTIVE layer
on the outside of worms made of CELLS
• CUTICLE• NON-CELLULAR PROTECTIVE
coating found on the outside of worms
http://www.nicksnowden.net/images/Taenia_scolex_drawing.gif
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TAPEWORM
• NO DIGESTIVE SYSTEM– absorbs nutrients through skin
• TEGUMENT protects them from host digestive enzymes and immune system
http://curezone.com/image_gallery/parasites/all/default.asp?i=66&n=75
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TAPEWORMS
• Can grow up to 30 ft – (2000 proglottids)
• REPRODUCE WITH PROGLOTTIDS– Add new proglottids behind scolex – Mature ones drop off at tail end – Leave body in feces
http://curezone.com/image_gallery/parasites/all/default.asp?i=65&n=75
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• MCDOUGALL VIDEO – CH.14 PREDATOR PREY 2 - TAPEWORM
EX: BEEF TAPEWORM
Adults attachinside intestinesand absorbdigested food
Proglottids arereleased in feces
Proglottids burst releasing eggs with larvae inside on ground
Cows eat grass; larvae travel through blood vessels;make cysts in muscle
Humans eat undercooked meatcontaining cysts
http://net.unl.edu/wonderwise/12parasi/a-para.htm46
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Pork Tapeworm (Taenia solium)
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Taenia saginata
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Source: Redrawn From Centers for Disease Control, Atlanta, GA.
Life Cycle of the Broad Fish Tapeworm
Diphyllobothrium latum
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Dipylidium caninum
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Echinococcus granulosus
• Parasite of dogs
– Host
• Juveniles in sheep, man and other mammals
– Intermediate host
• Hydatid cyst
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Hydatid Cyst
• Cysticercus – Juvenile stage
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