![]() ![]() The excretory system is responsible for osmoregulation and consists of blind-ending flame bulbs communicating through a duct system. In addition to the body wall, several other systems are common to the whole length of the tapeworm, including excretory canals, nerve fibers, and longitudinal muscles. Members of the Eucestoda have no mouth or digestive tract, and instead absorb nutrients through a layer of microtriches over the tegument at the shared body wall surface. These cytological processes are not well understood at present. As such, the main and largest section of the body, the strobila, consists of a chain of increasingly mature proglottids. ![]() The small neck region, directly behind the scolex, consists of an undifferentiated tissue region of proglottid proliferation, leading into a zone of increasing and continuous proglottid differentiation. The scolex, located at the anterior end, is a small (usually less than 1 mm) holdfast organ with specific systems for fastening itself to materials: rostrum, acetabula, suckers, bothria, grooves, and hooks. Most except caryophyllideans consist of a few to 4000 proglottids (segments) that show a characteristic body differentiation pattern into scolex (head), neck, and strobila. Almost all members, except members of the orders Caryophyllidea and Spathebothriidea, are polyzoic with repeated sets of reproductive organs down the body length, and almost all members, except members of the order Dioecocestidae, are protandral hermaphrodites. Examples are the pork tapeworm ( Taenia solium) with a human definitive host, and pigs as the secondary host, and Moniezia expansa, the definitive hosts of which are ruminants.Īdult Eucestoda have a white-opaque dorso-ventrally flattened appearance, and are elongated, ranging in length from a few millimeters to 25 meters. All tapeworms are endoparasites of vertebrates, living in the digestive tract or related ducts. Larvae have six posterior hooks on the scolex (head), in contrast to the ten-hooked Cestodaria. For the early name for a computer "worm", see Computer worm.Įucestoda, commonly referred to as tapeworms, is the larger of the two subclasses of flatworms in the class Cestoda (the other subclass is Cestodaria). ![]()
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