[1106 Exam 3 - Lab 37] Lab 37

[1106 Exam 3 - Lab 37] Lab 37 - Lab 37 I Intro A Flatworms...

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Lab 37 I. Intro A. Flatworms of phyla Platyhelminthes and roundworms of phyla Nematoda 1. Occur in marine, freshwater, terrestrial, and parasitic environments 2. Equipped with mesoderm tissue between ectoderm and endoderm a. This is solid between the two, so they are considered acoelomates ( no body cavity) & triploblastic b. Coelomates have organs in coelomic cavity 3. Have organs made of interdependent tissues and demonstrate bilateral symmetry 5. True organs and true tissues II. Phylum Platyhelminthes – Distinguished by acoelomate (no body cavity); does not have complete digestive tract. A. Class Turbellaria 1. Hermaphroditic – both sex organs 2. Genus Dugesia has sensory eyespots on its head a. Feeds by sucking food through mouth down into pharynx then into stomach b. Most digestion is extracellular, but phagocytic cells line the cavity c. Mesoderm tissue is a loose mass of cells, allowing for regeneration of parts B. Class Trematoda 1. Parasitic – either endo or ectoparasites (inside the body or outside the body) 2. Lack epidermis, but covered by metabolically active epicuticle made of proteins + fat a. Secreted by mesoderm that can resist digestive enzymes b. Has suckers that help in respiration and absorbing nutrients 3. Genus Opisthorchis parasitic in Japan and China a. These lay eggs in gallbladder and exit with feces b. Larvae hatch in fish and snails 4. Genus
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[1106 Exam 3 - Lab 37] Lab 37 - Lab 37 I Intro A Flatworms...

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