How is the sea cucumber body organized?

List tissues, organs and organ systems it has and how they work toghether to make it function.|||Sea cucumbers contain a calcareous ring that encircles the pharynx or throat. This ring serves as an attachment point for muscles operating the oral tentacles and for the anterior ends of other muscles that contract the body longitudinally. They contain a circle of oral tentacles. Another feature is the reduction of the skeleton to microscopic ossicles. In some species, the ossicles may be enlarged and plate-like.


As in other echinoderms, their water vascular system consists of an anterior ring canal from which arise long canals running posteriorly. They have a madrepore that opens into the coelom (body cavity).


Some sea cucumbers possess organs not found in other invertebrates. In some Aspidochirotida, the respiratory trees display Cuvierian tubules. In most species, these are apparently defensive structures. They can be expelled through the anus, whereupon they dramatically expand in length and become sticky, entangling or deterring would-be predators, such as crabs and gastropods. Many forms possess respiratory trees used in gas exchange. These are paired, heavily branched tubes attached to the intestine near the anus.