BIO 2135 Chapter Notes - Chapter DigiDiv: Water Vascular System, Tube Feet, Coelom

• School: University of Ottawa
• Department: Biology
• Course: BIO 2135
• Professor: Jon Houseman

Document Summary

Phylum echinodermata the opening of the water vascular system. Includes sea stars, sea urchins, brittle stars, sea cucumbers, basket stars. Water vascular system formed from the mesocoel of the tripartite coelom. Muscles contract and bend to move the organism. Body cavities (perivisceral cavity and water vascular system) are lined with cilia. Excretion occurs by simple diffusion across tube feel and dermal branchiae. Endoskeleton: formed from porous ossicles, fused into plates of separated and. Sea cucumbers use a hydrostatic skeleton, brittle stars use flexible arms hollow, fluid-filled tubes that are part of vascular system articulating. Nervous system = ring that surrounds the mouth, radial nerves down the arms. Mouth is in the center of the upper oral surface ( tegmen. Anus is on the oral surface, to one side at the top of the anal cone. Each branching arm has two rows of small lateral branches; pinnules. Triplets of tube feet on either side of the ambulacral groove.