WFSC 335Exam # 2 Study Guide Phylum Platyhelminthes - Flatworm- Acoelomate - Bilaterally symmetrical and sometimes display cephalizationwhere sensory organs tend to be towards the anterior endof the organism - Triploblastic - Dorso-ventrally flattened - 3 well developed muscle layerso Circularo Longitudinal o Oblique (transverse)Digestive System:- Mouth, pharynx, gastrovasuclar cavity o No anus b/c mouth is used for ingestion and egestionNervous System:- Ganglia (basic brain), transverse nerves, nerve cord, eyespot Excretory system:- Protonephiridia  flame cells, ducts, and pores- Excretory pore - Excretory canalsReproduction:- Hermaphrodites but do NOT self fertilize, reproduce sexually - Testissperm duct- Ovariesoviduct- Yolk gland 4 classes: 3 parasitic and 1 free living- Turbellia (free living)o Mostly aquatico Body covered with ciliao Rhabdites – secretions released by glands to form mucus; aid in movement o Most have eye spots except those species that live in caveso Auricle – ear like projections o Hermaphroditic but also reproduce asexually by fission or buddingo Vitellaria – female reproductive system o Planaria: Dugesia species Largest of freshwater triclads (4-30 mm in length)- Triclad – intestine has 3 branches, which is where the name triclad comes from Freshwater carnivores Move by using cilia- Monogeneao Have Syncytial epidermis – multinucleated cell mass from fusion of cells (one huge skin cell)o Marine and freshwater o Mostly ectoparasites of aquatic animals  1 host during lifecycle, no intermediate hosto Has suckers and clampso Opisthaptor – posterior hook attachment o Hermaphroditic (monoecious) Reproduce sexually inside hosto Direct development Free swimming larvae (gyrodactyloid)- Trematoda (“Flukes”)o Have Syncytial epidermis – multinucleated cell mass from fusion of cells (one huge skin cell)o Parasitic most have intermediate host (usually invertebrates) Endo and ectoparasites Reproduce asexually and sexually - Only reproduce sexually once in adult stage- Reproduce asexually in intermediate hosto 2 subclasses Aspidogastrea- Large ventral sucker divided by septa, forming row or suckers - Alveoli – suckerlets - Simple life cycle Digeneans (2 generations)- endoparasites (intestines)- life cycle: alternation of generation-like system composed of an asexual aspect (Polyembryony) invertebrate intermediate host and sexual phase (Anisogamy) vertebrate definitive host- incomplete digestive tract with no anus- Cestoda (Tapeworms):o Have Syncytial epidermis – multinucleated cell mass from fusion of cells (one huge skin cell)o Primarily found in intestines of vertebrates as adults and in the coelom of the definitive host o Adults usually have 2 or more suckers or sucking surfaces on specialized attachment called scolex (anchor)o No digestive organso Monoeciouso Indirect development with 2 hostso Body is made up of 4 segments Scolex (head) Immature proglottid Mature proglottid Gravid proglottido 1 set of male and female reproductive organs in each proglottid o Subclass Cestodaria Primitive tapeworms Mostly body cavity parasites (not intestinal tract) Neotenic – larva may be able to reproduce without adult stages Unsegmented body, no scolex Hermaphroditic no need for sexual reproduction and only 1 set of maleand female organs per individual unlike “true” tapewormso Subclass Eucestoda (True Tapeworms) Order Pseudophyllidea - Bothraited scolex – shallow sucking grooves- Vitellaria and testes scattered laterally- Genital pore located medially- Eggs operculated and protein tanned- Life cycles generally use 3 hosts2 intermediate hosts and the definitive host  Order Proteocephalata- Parasites as adults in freshwater fish,amphibians, and reptiles- Have acetabulate scolex – cup like witha muscular wall - Testes and vitellaria scattered laterallyin proglottids- Genital pore is laterally situated - Uterus is saccate Order Cyclophyllidea- Parasites as adults in birds and mammals - Life cycles are terrestrial NOT aquatic o Generally involve intermediate host o Larvae are some form of a bladder worm- Acetabulated scolex/rostellum present- Genital pores are laterally situated - Vitellaria compact in posterior region of proglottid- Important key terms:o Parenchyma – solid mesodermal, supportive tissue, fills acoelomate animalso Protonephridium – primitive osmoregulatory – excretory organ with tubules ending in specialized “flame cells”o Hermaphroditic – condition of having both male and female reproductive systems present in same individualo Tegument – unciliated living syncytium which forms the outer covering of certaininvertebrates such as trematodeso Muller’s Larva – free-swimming larva of certain polyclad flatwormso Syncytium – multinucleated mass of protoplasm resulting from the fusion of individual cellso Cirrus – eversible penis – like structure of flatwormso Laurer’s Canal – vestigial canal seen in certain flatworms; generally equivalent to a vaginao Onchomiracidium – larval form of monogenetic trematodeso Gyrodactyloid larva – larval stage of monogenetic trematodeso Opisthaptor – posterior hook attachment o Miracidium – first free – swimming larva of digenetic trematodeso Cercariae – polyembryonically produced, free-swimming or crawling larval stage of digeneao Metacercariae – encysted pre-adult stage in life cycle of most flukeso Ootype – female genital chamber where eggs are formed in certain Platyhelmintheso Sporocyst – germinal sac which is part of the polyembryony of flukeso Redia - A germinal mass found in the polyembryony of some flukes that is somewhat like sporocyst but which has a pharynx, locomotory buds and an intestinal cecum.o Scolex - Attachment organ of tapeworms.o Proglottid - The segment-like unit of the strobila of tapeworms.o Acetabulum - The ventral sucker used for attachment in flukes.o Aveola - The ventral sucker-like attachment organ of aspidogastrids.o Microthrix - The highly folded, specialized outer layer of the tegument of cestodes.o Cysticercus - The larval form found in the life cycles of certain cyclophyllidean tapeworms.o Gravid Proglottid - Proglottids of tapeworms which have become full of eggs.o Coracidium - The ciliated first larval stage of Pseudophyllidean tapeworms.o Lycophore