4. Flatworms-Platyhelminthes Least complex worm No body cavity (acoelomate) No respiratory system No circulatory system ◦All cells close to environment

7. Flatworms Three Classes ◦Turbellerians (Planarian) ◦Cestoda (Tapeworms) ◦Trematoda (Flukes)

9. Turbellarians Symmetry –Bilateral Structure ◦shovel head ◦flat body

12. NERVOUS SYSTEM Mass of nerve cells [ganglia] form a simple brain Ladder-like arrangement throughout body Head sensitive to touch, smell, and taste Two eyespots sensitive to light

14. REPRODUCTION Reproduction  Asexual  If cut into pieces – each piece will grow into new organisms  Split themselves apart  Sexual  Produce both male and female sex cells (hermaphodidic)  Cannot fertilize itself  Lay eggs

16. COOL! Planaria Regeneration An injury divided the head of this planarian in half. The two halves regenerated their lost parts. Eventually, the planarian will split lengthwise into two new planarians.

18. DigestionExcretion

20. The Monsters Inside Me

22. Class Trematoda Parasitic flukes a) Liver flukes b) Schistomomes / intestinal flukes that suck blood c) use snails as an intermediate host sucker

24. uterus testis ovary FLUKE – flat/parasitic Monoecious / hermaphroditic Class Trematoda

26. suckers SEM image

27. Intestinal Schistosomiasis 16 yr. Old boy Abdomen accumulates fluid- a body immune response to eggs embedded in tissues

29. Intermediate host Definitive host Schistosomiasis

31. Tapeworm showing proglottids Mature proglottids

33. Tapeworm scolex (head ) light microscope hooks suckers Immature proglottids)

34. Tapeworm scolex and hooks SEM image I love you

38. Flea larva eats tapeworm eggs. Tapeworm larvae develop inside flea Worm grows in dog Dog eats infected flea Proglottids with eggs leave in wastes

44. Rotifer video 2:30 Rotifer 1:30 Rotifer feeding

49. Egg produced by adult exits in host in feces Host ingests eggs Hatch in host intestine Migrate to lungs as larva Molt in lungs Migrate to trachea, carried to stomach Adult stage in host intestine.

51. Eggs ingested by host Organism matures in host large intestine Adult lives in host large intestine Adult migrates to perianal region to lay eggs at night Host gets eggs on fingers

52. Eggs hatch in feces Develop into larva in the mud/soil Penetrate host skin through toes Enters circulatory system Migrates to lungs Matures and migrates to trachea Swallowed by host Adult stage in small intestine Eggs produced