BIO 5 Lecture Notes - Lecture 5: Choanocyte, Homoscleromorpha, Osculum
Document Summary
Group of cells: pinacocytes similar to epithelial tissue cells. (epi lining and protection) line/cover the outside of the body. also line some of the internal passage waves in some groups, mesohyl middle layer of the sponge. Gelatinous material with embedded cells, fibers and skeletal elements: archaeocytes - ameboid cells. Can differentiate into other cell types in the sponges body. Help distribute nutrients, digestion, and reproduction etc: sclerocytes secrete spicules which are skeletal elements, chemical composition of spicules calcareous caco3, siliceous silica, spongocytes secrete spongin, choanocytes help move water through the sponge bob. So they spicules which keeps them in the sponge phylum. Class homoscleromorpha: have a pillow mound form, the ponagrow site are, they don"t have actual junctions present in an epithelial. Focus on class calsisponge: spicules have calcium carbonate spicules, include asconoid, syconoid and leuconoid species. Class hexactinellida: has siliceous spicules, syconoid or leuconoid canal systems, syncytial body, choanoblasts.
