Hopkins Marine Station Student Paper

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(full paper is archived in the Miller Library)

Title: The connection between the hemal and digestive systems of the holothuroid, Parastichopus californicus
Student Author(s): Vandeweghe, Heather
Pages: 28
Location: Final Papers Biology 175H
Date: June 1983
Keywords: echinoderms
Abstract: The hemal system and its association with the intestine was investigated in P. californicus. Two main vessels run along the length of the intestine; the dorsal hemal vessel is attached to the intestine by small dorsal connections and the ventral vessel lies nearly on top of the intestine. The dorsal vessel beats about every eighteen to twenty seconds, creating a flow patttern of the hemal fluid. The association of the hemal fluid with the intestine was determined by the use of cobalt and latex injections. It was concluded that the hemal fluid flows through concentric folds that face the lumen of the intestine. The transport of absorbtion of small molecules from the lumen of the intestine into the hemal vessels occurs within a fairly short time -- fifteen minutes -- but the passage of larger molecules is blocked.