BIOL 2325 Lecture Notes - Lecture 3: Adherens Junction, Zoantharia, Homoscleromorpha
Document Summary
Spicules-skeleton made of calcium carbonate or silica and collagen. Oscula- large pour that serves as a water outlet. Choanocytes- peculiar flagellated collar cells whos flagella maintain a current of environmental water through the canals that they line. There are 3 types of canal systems: asconoid, syconoid, and leuconoid. Sexual-sperm released by one individual into water and taken in by another. Calcium carbonate spicules with 1, 2, or 4 rays. Glass sponges with 6 rayed siliceous spicules. Body is syncytial(many nuclei in one cell) Bilayered-between layers is collagenous mesophyll where choanoblasts and archaeocytes occur. Spicules bound together in glass like lattice. Has a basement membrane but not a true tissue-incipient epithelium. Cells of pinacoderm attach to ecm with adherens junctions but do not attach to each other via desmosomes. 2 body types- free swimming medusa or sessile polyps. Digestion- large gastral cavity partitioned by septa(inward extensions of the body wall) Use adhesive disk to attach to seaweed.
