What characteristics of phylum Cnidaria are most important in distinguishing it from other phyla.doc

Parenchyma a spongy mass of vacuolated mesenchyme

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a small head bearing hooks and suckers. Parenchyma- a spongy mass of vacuolated mesenchyme cells filling spaces between viscera, muscles, or epithelia liver fluke- any of various trematode worms that invade the mammalian liver; especially : one of the genus Fasciola (F. hepatica) that is a major parasite of the liver, bile ducts, and gallbladder of cattle and sheep, causes fascioliasis in humans, and uses snails of the genus Lymnaea as an intermediate host proglottid- Boxlike portion of a tapeworm containing a set of reproductive organs; usually corresponds to a segment acoelomate- without a coelom, as in flatworms and proboscis worms eucoelomate- Any of the animals with "true" coelom, which is characterized by a body cavity completely lined with a peritoneum that attaches to organs triploblastic- the embryo has three primary germ layers- ectoderm, mesoderm, and endoderm diploblastic- organism with two germ layers - endoderm and ectoderm cercaria- tadpolelike larva of trematodes (flukes) sporocyst- a larval stage in the life cycle of flukes; it originates from a miracidium scolex- an attachment organ or holdfast of a tapeworm; bears suckers and in some hooks and posterior to it new proglottids are differentiated. Trichina- a parasitic nematode worm of humans and other mammals, the adults of which live in the small intestine. The larvae form hard cysts in the muscles, where they remain until eaten by the next host. Dirofilaria- A genus of filarial worms including the heartworm and other species, usually found in mammals other than humans. Opisthaptor- posterior attachment organ of a monogenetic trematode Miracidium- a minute ciliated larval stage in the life of flukes. flame cells- specialized hollow excretory or osmoregulatory structure of one or several small cells containing a tuft of flagella and situated at the end of a minute tubule; connected tubules ultimately open to the outside Contrast asexual reproduction in triclad flatworms, trematodes, and cestodes Triclad flatworms: Asexual reproduction of Flatworms Can reproduce asexually or sexually. Asexually they reproduce by fission. They have the ability to regenerate missing parts. Trematodes: Undergo asexual reproduction in their intermediate snail hosts. Miracidium enters the tissues and transforms into a sporcyst which produces one generation of redae which gives rise to the cercariae. These two asexual stages in the inermediate host allow a single miracidium to produce over 250,000 cercaria. Cestodes: Budd off hundreds of offspring. also known to cross fertilize and self fertilize. When raw or undercooked measly meat is eaten by a suitable host the cyst wall dissolves scolex attaches to the intestinal mucosa and proglottids begin to develop. Contrast the typical life cycle of a monogenean with that of a digenetic trematode Monogenean- Direct with single host.. the egg hatches to produce ciliated larva which attach to host on skin or gills.
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Digenetic: indirect with multiple hosts. The first host is a mollusc and the definitive host is a vertebrate.
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  • Fall '15
  • Zoology, Body cavity, Annelid, larval stage, digestive tract, mantle cavity

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