BIOL 2030 Lecture Notes - Mesohyl, Choanocyte, Mesoglea

• School: York University
• Department: Biology
• Course: BIOL 2030
• Professor: Scott Kelly

Document Summary

[sponges] phylum of simple multicellular animals, with a simple body enclosing a single central cavity (in simple sponges) or penetrated by numerous interconnected cavities. The body wall consists of an outer layer of epithelium seprated from an inner layer of ciliated choanocytes (feeding cells) by a mesogleal layer. Water is drawn into the internal cavities through pores (ostia), food particles are taken up by the choanocytes and the water flows out through a large pore (the osculum). There are three classes: the calcarea, the calcareous sponges, which have spicules of calcium carbonate embedded in the mesoglea and projecting to the outside; the hexactinellida, the glass sponges, with silica spicules; and the. Demospongia, which includes some species with silica spicules and some species without, and which often have the body wall strengthened by a tangled mass of fibres (ex. Apopyle exhalent pore of sponges (leading from radial canal to spongocoel) Archeocyte amoeboid cells found in the mesohyl of sponge.