helminths-1 - 5. Life cycle - complex (see text) III....

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HELMINTHS I. Characteristics A. Kingdom Animalia B. Complex, multicellular, eucaryotic C. Have head and tail D. Bilaterally symmetrical E. Simple organ systems - in body cavity F. Adults - macroscopic G. Eggs, larvae - microscopic II. Platyhelminthes - Flatworms A. Flattened body shape B. Hermaphroditic C. Lack a digestive system, or very simple D. Some have complex life cycles involving intermediate hosts, immature stages E. Parasitic forms possess thick cuticle covering body surface - protection from host digestive enzymes F. Cestodes - Tape worms 1. Scolex - head with suckers, hooks - attachment to intestinal wall 2. Body - flattened sections - proglottids 3. Eggs produced in proglottids 4. Parasitizes intestinal tract - absorbs nutrients 5. Infection due to consumption larvae in raw, undercooked meat 6. Life cycle tape worm (see text) G. Trematodes – Flukes 1. Body shape - flat, leaf-like 1
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2. Oral, ventral suckers - attachment 3. Male, female reproductive organs 4. Can infect blood, lung, liver
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Unformatted text preview: 5. Life cycle - complex (see text) III. Aschelminthes- Round worms A. Rounded body shape B. Dioecious - separate sexes C. Possess digestive system with mouth and anus. D. Life cycles - some include intermediate hosts, immature stages E. Enterobius vermicularis- Pin worms 1. Infection due to ingestion of eggs 2. In intestine eggs hatch mature adults 3. At night adult female lays eggs on skin in perianal region (See fig. in text) F. Necator americanus- Hook worms 1. Mouth parts hook-like - attach to intestinal wall 2. Feeds on blood of host 3. Eggs passed in stool 4. Larvae in soil penetrate skin of host 5. Blood lungs small intestine (see life cycle in text) G. Trichinella spiralis 1. Larvae encyst in muscle of infected pig. 2. Infection due to consumption of poorly-cooked pork. 3. Larvae becomes encysted in host muscles 2...
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helminths-1 - 5. Life cycle - complex (see text) III....

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