2. Platyhelminthes

3. Contents Position in animal kingdom Taxonomy Some unique characteristics Systems 1 (Integumentary, Skeletal, Muscle and Digestive)Systems 1 Systems 2 (Excretory, Respiratory, Circulatory, and Nervous).Systems 2 Systems 3 (endocrine and Reproductive)Systems 3 Class TurbellariaTurbellaria Class TrematodaTrematoda Class CestodaCestoda

4. Platyhelminthes Eumetazoa - animals with tissue  Bilateria - have bilateral symmetry and are triploblastic. Protostomia - a group of animals whose mouth develops from the blastopore, and the mesoderm forms from an area near the blastopore. Acoelomata - They have a true mesoderm which fills the original blastocoel between the outer epidermis and digestive tract.

5. Taxonomy Class Turbellaria (tur-bell-er-e-a)Class Turbellaria (tur-bell-er-e-a)  Dugesia Dugesia Class Monogenea (mon-o-gin-e-a)  No representatives Class Trematoda (trim-a-toe-da)Trematoda (trim-a-toe-da)  Clonorchis, Fasciola, Schistosoma ClonorchisFasciolaSchistosoma Class Cestoda (ces-toe-da)Cestoda  Taenia, Dipylidium Echinococcus TaeniaDipylidium Echinococcus Contents

6. Some Unique Characteristics Proglotids and scolex in Cestoda Rabdites in Turbellaria Combination of characteristics- flame cells and being acoelomates for example. Larva of each class are unique Contents

7. Systems 1 IntegumentaryIntegumentary - Rhabdites and one cell layer epidermis in Turbellaria and usually ciliated; syncytial tegument in other classes. SkeletalSkeletal - hydrostatic MuscleMuscle - longitudinal, transverse, and circular muscles are present. DigestiveDigestive - incomplete with intracellular and extracellular digestion; no system in Cestoda.

8. Systems 2 ExcretoryExcretory - flame cells, or excretory tubes in Cestoda. RespiratoryRespiratory - no system, diffusion CirculatoryCirculatory - none, diffusion. NervousNervous - anterior ganglia, ventral ladder-like system (two lateral cords with transverse cords). Contents

9. Systems 3 EndocrineEndocrine - hormones produced by nervous system ReproductiveReproductive - monoecious in most  Well developed reproductive organs, mostly internal fertilization.  Two of the parasitic classes have complex life cycles Trematoda - miracidium, sporocyst, redia, cercaria, metacercaria (usually snail is secondary host. Cestoda - oncosphere, cystercercius (bladderworm) Contents

10. Class Turbellaria Planaria -Free-living flatworms with soft flattened bodies covered with ciliated epidermis which has special secreting cells called rabdites. Dugesia Contents

11. Class Trematoda Flukes -oral and ventral suckers, no hooks, parasites, body with a syncytial tegument without cilia. Larva stages unique. Clonorchis Fasciola Schistosoma Contents

12. Clonorchis Human liver fluke - has two intermediate or secondary host snail and fish. Contents Cerceria Human liver fluke

13. Fasciola Sheep liver fluke - metacercaria on grass. Life cycle Contents

14. Fasciola life cycle Contents

15. Schistosoma Blood Flukes  Cerceria usually infect by burrowing through skin. Contents

16. Class Cestoda Tapeworms Have distinct head structure (Scolex) and reproductive units called proglottids. Do not have a digestive system. Larva are oncospheres and cysticerci (bladder worms)  Taenia Taenia  Dipylidium Dipylidium  Echinococcus Echinococcus Contents

17. Taenia Proglotid Contents

18. Dipylidium (dog tape) Juveniles in flea and louse Note the two gential pores and reproductive systems in each proglottid. Proglottid Contents

19. Echinococcus Hydatid cyst (cysticercus)- may scolices and enlarges to as large as a basketball. Often called sand. Only three proglottids Contents

20. End of Presentation