BIOL 1202 Chapter : Chapter 33
Document Summary
Concept 33. 1: sponges are basal animals that lack true tissues. Porifera: phyla calcarea and silicea = sponges. Live in both fresh and marine waters. Sponges are suspension feeders: filter water passing through their bodies. Spongocoel: water is drawn through pores and into its central cavity. Choanocytes: lines the interior of the spongocoel; also called collar cells (named for the membranous collar around the base of the flagellum) Osculum: large opening where water flows out. Mesohyl: a gelatinous region that separates two layers of cells in the body of a sponge. Amoebocytes: they wander through the mesohyl, powered by pseudopodia. Functions: take up food from the water and from chaonocytes, digest it, and carry nutrients to other cells; manufacture tough skeletal fibers within the mesohyl. Some of these skeletal fibers are sharp spicules made from calcium carbonate or silica. Porocyte: water enters through the epidermis through pores formed by doughnut-shaped cells that span the body wall.
