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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This note was uploaded on 10/18/2011 for the course MCB 3020 taught by Professor White during the Spring '09 term at University of Central Florida.

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

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