BIO 112 Lecture Notes - Lecture 6: Madreporite, Ampulla, Coelom
19 Oct 2016
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Document Summary
Dermal ossicles with spines and a water vascular system. Star shaped with arms broadly connected to central disc; arms in fives. Star shaped with arms sharply demarcated from central disc; arms in fives. Pin-cushion or disc shaped; rows of tube feet in fives. Special jaw: aristotle"s lantern, ossicles overlap to form a test. Cucumber shaped; rows of tube feet in fives. Body wall: epidermis, ossicles (calcareous plates) with spines, muscles. Coelom with organs and water vascular system. Seas stars have two stomachs, massive digestive glands, and a short intestine. Chemoreceptors, tactile receptors; eyespots on tips of arms in some sea stars. Nerve ring in center, radial nerves in each arm/tube foot row; no brain. Rows of tube feet powered by water vascular system. Hydraulic system of fluid filled canals ending in tube feet. If part of central disc attached to arm, some can regenerate a whole new animal. Egg get fertilized, develops into larva larva is bilateria.
