BIOL 2030 Chapter Notes - Chapter 2: Pharynx, Dugesia, Gastrointestinal Tract
26 Feb 2017
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Water enters the sponge through small pores and exits through the large pore, osculum. Outer surface is covered with flat cells called pinacocytes; these help the song firmly attach to its substrate. Water enters through the incurrent pores on the body wall; then passing though the incurrent canal into the radial canal. Radial canals are lined with choanocytes (cid:131) choanocytes generates the feeding current as well as phagocytize food particles. Body wall consist of: pinacocytes, inner choanocyte layer and the middle mesohyl(contains a gelatinous protein matrix) Where the tentacles are located, the batteries of nematocysts, the hypostome(where mouth is supported), mouth and base can also be found. Some species may have a bud and/or ovary or testis. Gastrodermis possesses flagellated nutritive muscle cells and gland cells. Identify: (cid:190) epidermis (cid:190) gastrodermis (cid:190) gastrovascular cavity (cid:190) mesoglea (cid:120) (cid:120) Gastrozoid: feeding polyp (cid:131) consists of tentacles, mouth and hypostome.
