1 Phylum Platyhelminthes

2 Flatworms Triploblastic Acoelomate Bilateral symmetry Hermaphroditic (Most) –Monoecious One opening for digestive system - incomplete gut Paired lateral nerve cords & cerebral ganglion Flame cells - modified excretory cells

3 Acoelomate EctodermMesodermEndoderm

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5 Nervous System Lateral nerve cord Connectives Auricle Eye spot Cerebral ganglion

6 Excretory System Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

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8 Class Turbellaria Eye spots - Ocelli Ciliated surface Dual Adhesion Glands - to attach and release Regenerate if cut Most are free-living Detect food by chemoreceptors Detect Water Current - statocysts Sexual Reproduction: –Internal Fertilization –Cocoon attached to plants

9 Releasing and Attaching (Viscid) Glands

10 Turbellaria Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

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12 Class Trematoda Flukes Parasites - endoparasitic Holdfast devices –Hooks and Suckers Complex life cycle Intermediate host –Animal with juvenile stage Definitive host –Animal with adult stage

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14 Chinese liver fluke 50 million people Cirrhosis of liver Diarrhea Pain

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16 General Trematoda (FLUKE) Life Cycle General Trematoda (FLUKE) Life Cycle Egg passes from definitive host and must reach water Egg passes from definitive host and must reach water Hatches into a free-swimming ciliated larva, the miracidium Hatches into a free-swimming ciliated larva, the miracidium Miracidium penetrates tissues of a snail Miracidium penetrates tissues of a snail Transforms into a sporocyst Transforms into a sporocyst Sporocyst reproduces asexually to form redia Sporocyst reproduces asexually to form redia Rediae reproduce asexually and form cercaria Rediae reproduce asexually and form cercaria Cercaria attach to fish and form cysts in muscle tissue Cercaria attach to fish and form cysts in muscle tissue

17 Sheep liver fluke Sheep, cattle and man –Weight loss Eat vegetation with metacercaria

18 Intestinal fluke 10 million people Man and pigs Hemorrhage and abscesses of small intestine

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20 Lung fluke Carnivores, pigs, rodents and man May be fatal

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22 Lung Fluke Distribution

23 Schistosoma Blood flukes/Liver 200 million people infected 1 million deaths/year Sexes are separate Pierce through Skin

24 Life Cycle of a Schistosome Fluke Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Cut Liver of individual who dies from hematemesis (vomiting blood). 180 adult blood flukes were found in autopsy

26 Schistosome Swimmers Itch - Schistosoma Dermatitis –Cercaria penetrate wrong host –skin becomes irritated and inflammed = itch Cercaria have forked tail

27 Swimmers Itch

28 Class Cestoidea Tape worms No digestive system 40 feet long Individual units = proglottids –Contain own reproductive structures and organs

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30 Scolex

31 Proglottid Uterus Testes Ovary Yolk gland Vas deferens Seminal receptacle

32 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pork Tapeworm (Taenia solium)

33 Taenia saginata

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