Phylum platyhelminthes information Continue The name Phytome Platyhelminthes literally means flatworms. Members of this filum are soft, lean, leafy or tapeworms, including a familiar planarium of ponds and streams, as well as flukes and tapeworms, parasitic in the human body and other animals. Some of the defining characteristics of the filum are that flatworms are acoelomatitis (they do not have a body cavity), a tripleblast (the body has three layers of tissue), and are bilaterally symmetrical (they have a symmetrical right and left side and usually a certain head), and they have organ systems, including the excretion, digestive, reproductive and nervous system, but not the respiratory system. The Turbellaria class includes all free living members of the filum as well as several parasites. It includes many marine forms, whose beautiful colors serve as a warning of their toxicity to new predators, as well as more gray freshwater planarians (Dugesia). Some Turbellaria can float along the wavy fields of the body, but most of them gracefully glide over surfaces along the mucus trail, pushed by cilia on their abdominal surface. The Trematoda class, commonly referred to as flukes, are unsegmented parasitic flatworms that usually parasitize the snails as an intermediate host (in which they breed aloper) and human or other vertebrates as the final host (in which the worms mate and lay eggs). Many species have other hosts between the two, such as fish or frogs. Trematodes usually have a pair of suckers to scan and clinging to the host's tissue. Many people are infected with blood flukes, hepatic flukes, pulmonary flukes, and other trematode parasites of great medical importance. Cestoda, commonly called tapeworms, are segmented, tape-like parasites commonly found as adults in the small intestines of vertebrate animals. Unlike other classes, they do not have a digestive tract because they can absorb pre-ing ingested nutrients from the host's intestines. The body consists of a long chain of segments, each with its own reproductive system. The front end is a knoblike holdfast called scolex, equipped with suckers and often hooks for attaching to the host's intestines. In general, tapeworm infections are not as serious since medically as trematode infections, but some tapeworms can be fatal. Pechenik, Ian A. Biology of invertebrates, 4th Ed. Boston: McGraw Hill, 2000. Schmidt, Gerald D. and Larry S. Roberts. The basics of parasitology, 6th ed. Dubuque, IA: McGraw-Hill Higher Education, 2000. The American zoologist is known for his authoritative six-volume treatise on invertebrates, whose own specialty were hydras and flatworms. went to college, despite her family's objections. In the last years of her life she lived for money and worked at the American Museum of Natural History. Other articles that you would like: follow City-Data.com Founderon our forum or Twitter Phil Myers Flatworms are are bilateral symmetrical worms that do not have coelom (akeloma) but which have three layers of microbes. Some form of free life, but many are parasitic. Flatworms have a head nervous system that consists of a ganglion of the head, usually attached to longitudinal nerve cords that are interconnected throughout the body by transverse branches. Excretion and osmolegulation by flatworms is controlled by fire cells located in protonefridi (they are absent in some forms). Flatworms have no respiratory or circulatory system; These functions occur by absorption through the wall of the body. Non-parasitic forms have a simple, incomplete intestine; even this is lacking in many parasitic species. The movement of some flatworms is controlled by longitudinal, circular and oblique layers of muscles. Others move along the mucus trails by beating epidermal cilia. The development of directional movement correlates with cephalization. In some flatworms, the process of cefalization involves the development in the head area of light-sensitive organs called ocelli. Other senses found in at least some members of this group (not necessarily on the head) include less than receptors, balance receptors (statocysts), and receptors that sense the movement of water (rereceptors). Most flatworms can reproduce sexually or asexually. Most of them are monotonous. Most have developed ways to avoid self-enrichment. The development can be direct (eggs hatch in tiny worms that resemble adults) or indirect (with a cilized larvae form). Flatworms include a large number of parasitic forms, some of which cause great damage to human populations. Click on the class name below to learn more: Turbellaria Class (turbellarians, flatworms) Class Monogenea (parasitic flukes) Class of Trematode (parasitic flukes) Class Cestoda (tapeworms) Source: Hickman, C.P. and L.S. Roberts. 1994. Diversity of animals. Wm. C. Brown, Dubuque, IA. Bruska, R.K., and G.J. Bruska. Invertebrates. 1990. Sinauer Associates, Sunderland, Massachusetts. Phil Myers (author), Museum of zoology, University of Michigan-Ann Arbor. Platyhelminthes are flat worms that do not have coelom; many of them parasitize; all have no circulation or respiratory system. Learning GoalsIndear among the classes platyhelminthes Key points Of Platyhelminthes are acoelomat flatworms: their bodies are firm between the outer surface and the digestive system cavity. Most flatworms have a gassy cavity rather than a full digestive system; The same cavity used for food foremining is used to dispose of waste. Platyhelminthes are either predators or scavengers; many of them are parasites that feed on the tissues of their hosts. Flatworms simple nervous system, without circulation or respiratory system, and most of them produce both eggs and sperm, with internal fertilization. The plates are divided into four classes: classes: Free-to-inhabited marine species; Monogenea, fish ectoparasites; Trematode, internal parasites of humans and other species; and Cestoda (tapeworms), which are the internal parasites of many vertebrates. In flatworms, overcooked materials are taken into the intestinal cells lining phagocytosis rather than being processed internally. Key terms acoelomate: any animal without coelom, or ectoparase body cavity: a parasite that lives on the surface of the host organism scolex: the structure on the back of the tapeworm, which, as an adult, has suckers and hooks with which it attaches to the host proglottid: any of the segments of the tapeworm; they contain both male and female reproductive organs Phylum Platyhelminthes consists of flatworms: acoelomacological organisms that include many free life and parasitic forms. Most flatworms are classified as superfilum Lophotrochozoa, which also includes molluscs and annelids. Platigelmints consist of two lines: Katenulida and Rabditopkhora. Catenulida, or chainworms is a small hoard of just over 100 species. These worms usually breed asexual, budding. However, the offspring are not completely separated from their parents; so they resemble a chain. The rest of the flatworms discussed here are part of The Rabditopor. Many flatworms parasitize, including important human parasites. Flatworms have three layers of embryonic tissue that enable surfaces that cover tissue (from ectoderm), internal tissue (from mesoderm), and digestive system lines (from endoderm). Epidermal tissue is a single- layer cell or layer of fused cells (syncytia), which covers a layer of circular muscle over a layer of longitudinal muscle. Mesodermal tissues include mesenchymal cells that contain collagen and support secretory cells that secrete mucus and other materials on the surface. Flatworms are acoelomamatoma: their bodies are firm between the outer surface and the digestive system cavity. Free-living species of flatworms are predators or scavengers. Parasitic forms feed on the tissues of their masters. Most flatworms have a gassy cavity rather than a full digestive system; In such animals, the mouth is also used to expel waste from the digestive system. Some species also have an opening. The intestines can be a simple bag or highly branched. Digestion is extracellular, with digested materials taken into the intestinal cells lining with phagocytosis. One group, destodam, lacks a digestive system. The flatworms have a excretory system with a network of tubes throughout the body with holes for the environment and nearby flame cells, whose cilia beat to send the waste fluids concentrated into the tubes from the body. The system is responsible for regulation salts and the release of nitrogen waste. Teh Teh The system consists of a pair of nerve ligaments running the length of the body with the connections between them and a large ganglion or the concentration of nerves on the front of the worm, where there may also be a concentration of photosensory and chemosensory cells. There is no circulatory or respiratory system, and gas and nutrient metabolism depends on diffusion and cell-cell compounds. This necessarily limits the thickness of the body in these organisms, limiting them to flat worms. In addition, most types of flatworms are monoesive; Usually, fertilization is internal. Asexual reproduction is common in some groups. Platigelmints are traditionally divided into four classes: Turbellaria, Monogene, Trematoda and Sestod. The Turbellaria class includes mostly free-living marine species, although some species live in freshwater or humid terrestrial environments. The vent epidermis of the Turbellarians is called, which facilitates their movement. Some Tourbellarians are capable of remarkable feats of regeneration: they