1 Phylum Platyhelminthes Zoology WCHS

2 Phylum Platyhelminthes Flat worms Triploblastic= 3 tissue layers Acoelomate Bilateral symmetry Hermaphroditic 1 opening for digestion Simple nervous and muscular systems Flame cells May be free living or parasitic CEPHALIZATION

3 Acoelomate EctodermMesodermEndoderm Digestive cavity is the only inner cavity

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5 Phylum Platyhelminthes: Class Turbellaria Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Acoelomate

6 Other Body Plans: Pseudocoelomate EctodermMesodermEndoderm Fluid filled cavity between the endoderm and ectoderm- pseudocoelom Differs from a true coelom because…. It is not entirely lined with mesoderm tissue Organs are not suspended or attached to membranes (mesenteries)

7 Other Body Plans: Coelomate EctodermMesodermEndoderm Epithelial lined cavity between digestive tract and body wall

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Flatworm Body Systems No Circulatory or Respiratory systems- simple diffusion through body wall Systems Present- Digestive Nervous Excretory Reproductive 9

Flatworm Body Systems: Digestive Incomplete- mouth pharynx (to swallow food) intestine(no anus) 10

11 Nervous System Lateral nerve cord Eye spot= detects light anterior ganglion transverse nerve cord sensory receptors

12 Cephalization=“Primitive Brain” Auricle Cerebralganglion Paired nerve cords

13 Excretory System Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. -Gets rid of nitrogenous wastes - protonephridia- first kidney Components: -Flame cells -Excretory ducts/tubes -pores

14 Reproductive System Sexual and asexual reproduction sexual- eggs + sperm asexual- regeneration Hermaphrodites- both male (penis and testis) and female organs(vagina and ovary)

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Kingdom Animalia Phylum Platyhelminthes Classes: Turbellaria Trematoda Cestoda 16

17 Class Turbellaria Most free-living Aquatic Eye spots Regenerate if cut in two Ex. Planaria

Planarians Free-living flatworm bilateral symmetry Lives in fresh water usually under leaves and rocks Usually feeds on dead or slow moving organisms

Planarian Reproduction Reproduction: Sexually: hermaphrodites Asexually: can regenerate missing body parts (called fission) What would happen ???? Detaches its tail end and each half regrows the lost parts each Planaria gives and receives sperm

Planarians: body structures Nervous/sensory system: Brain-like structure Nerve cord: carries impulses down body Eyespots: sense light and dark Sensory pits: line sides of head to aid in movement and sensing surroundings Flame Cells: remove excess water and nitrogenous wastes

Planarians: body structures Digestive/excretory system Mouth: located in center of ventral side Pharynx: tube like structure which extends from mouth during feeding; acts like a straw sucking up food and carrying it to body Food enters mouth and solid wastes exit mouth eyespot ganglion Gastrovascular cavity Mouth pharynx Flame cells ganglion Nerve cord LABEL YOUR PLANARIAN!!!

22 Class Trematoda Parasites Holdfast devices –Endoparasites Complex life cycle- larval stage in one or more hosts Primary host-juvenile/larva stage- sexual reproduction Secondary host- adult stage, asexual reproduction Ex. Blood and liver flukes

Flukes Blood fluke life cycle: Eggs are released in water from wastes of infected host Hatch in to swimming larvae in water Larvae enter a host (like a snail) where they develop & mature Enter water again and bore into skin of new host (man) From the blood stream they bore into intestines where they attach and feed on blood

24 Schistosoma Blood flukes 200 million people 1 million deaths/year

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

26 Schistosome Cercaria have forked tail

27 Swimmers Itch

28 Clonorchis sinensis human liver fluke Oral suckerIntestineUterusYolk gland TestesOvarySeminal recepticle

29 Clonorchis sinensis Chinese liver fluke 50 million people Cirrhosis of liver Diarrhea Edema Pain

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31 Fascioloa hepatica Sheep liver fluke Sheep, cattle and man –Weight loss Eat contaminated vegetation

32 Life Cycle of the Sheep Liver Fluke Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

33 Paragonimus westermani Lung fluke Carnivores, pigs, rodents and man May be fatal

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36 Class Cestoda: “cess pool” Tape worms All parasitic Live in intestines of vertebrates No digestive system 40 feet long

Tapeworm structures Scolex= head hooks and suckers to aid in attachment to intestine Proglottids: individual parts of worm –Each one is detachable –Each proglottid may contain up to 100,000 eggs which fall off when full –When released, they exit with the host’s wastes

Tapeworm life cycle Eggs hatch in intestines of intermediate host (pig or cow) Young worms burrow out of intestine into pig’s muscle tissue forming cysts Secondary host (man) eats undercooked/raw meat containing worm larvae cysts Larvae hatch and mature in intestines Attach to intestines, soak up digested food of host May enter bloodstream and infect other tissues

39 Scolex

40 Proglottid Uterus Testes Ovary Yolk gland Vas deferens Seminal receptacle

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

42 Taenia saginata

43 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

44 Dipylidium caninum

45 Echinococcus granulosus Parasite of dogs –Host Juveniles in sheep, man and other mammals –Intermediate host Hydatid cyst

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47 Hydatid Cyst Cysticercus –Juvenile stage

48 Adult stage in dog Ecinococcus granulosus

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