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Typhlosole
{{Unreferenced, date=December 2009 A typhlosole is an internal fold of the intestine or intestine inner wall. Typhlosoles occur in bivalve mollusks, lampreys and some annelids and echinoderms. In earthworms, it is a dorsal flap of the intestine that runs along most of its length, effectively forming a tube within a tube, and increasing the absorption area by that of its inner surface. Its function is to increase intestine surface area for more efficient absorption of digested nutrients. In different earthworm families, the typhlosole appears to have multiple origins. The Lumbricidae, for example, have a typhlosole which is an infolding of all layers of the intestine wall, whereas in some other families (e.g. Megascolecidae), it is an infolding of only the inner layer, and in many earthworms it is absent. See also *body cavity A body cavity is any space or compartment, or potential space, in an animal body. Cavities accommodate organs and other structures; cavities as potentia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Body Cavity
A body cavity is any space or compartment, or potential space, in an animal body. Cavities accommodate organs and other structures; cavities as potential spaces contain fluid. The two largest human body cavities are the ventral body cavity, and the dorsal body cavity. In the dorsal body cavity the brain and spinal cord are located. The membranes that surround the central nervous system organs (the brain and the spinal cord, in the cranial and spinal cavities) are the three meninges. The differently lined spaces contain different types of fluid. In the meninges for example the fluid is cerebrospinal fluid; in the abdominal cavity the fluid contained in the peritoneum is a serous fluid. In amniotes and some invertebrates the peritoneum lines their largest body cavity called the coelom. Mammals Mammalian embryos develop two body cavities: the intraembryonic coelom and the extraembryonic coelom (or chorionic cavity). The intraembryonic coelom is lined by somatic and splanchnic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earthworm
An earthworm is a terrestrial invertebrate that belongs to the phylum Annelida. They exhibit a tube-within-a-tube body plan; they are externally segmented with corresponding internal segmentation; and they usually have setae on all segments. They occur worldwide where soil, water, and temperature allow. Earthworms are commonly found in soil, eating a wide variety of organic matter. This organic matter includes plant matter, living protozoa, rotifers, nematodes, bacteria, fungi, and other microorganisms. An earthworm's digestive system runs the length of its body. An earthworm respires (breathes) through its skin. It has a double transport system made of coelomic fluid that moves within the fluid-filled coelom and a simple, closed circulatory system. It has a central and peripheral nervous system. Its central nervous system consists of two ganglia above the mouth, one on either side, connected to a nerve running along its length to motor neurons and sensory cells in each s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gut (anatomy)
The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and other animals, including the esophagus, stomach, and intestines. Food taken in through the mouth is digested to extract nutrients and absorb energy, and the waste expelled at the anus as feces. ''Gastrointestinal'' is an adjective meaning of or pertaining to the stomach and intestines. Most animals have a "through-gut" or complete digestive tract. Exceptions are more primitive ones: sponges have small pores ( ostia) throughout their body for digestion and a larger dorsal pore (osculum) for excretion, comb jellies have both a ventral mouth and dorsal anal pores, while cnidarians and acoels have a single pore for both digestion and excretion. The human gastrointestinal tract consists of the esophagus, stomach, and intestines, and is div ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bivalve
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bivalves have no head and they lack some usual molluscan organs, like the radula and the odontophore. They include the clams, oysters, cockles, mussels, scallops, and numerous other families that live in saltwater, as well as a number of families that live in freshwater. The majority are filter feeders. The gills have evolved into ctenidia, specialised organs for feeding and breathing. Most bivalves bury themselves in sediment, where they are relatively safe from predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. Some bivalves, such as the scallops and file shells, can swim. The shipworms bore into wood, clay, or stone and live inside these substances. The shell of a bivalve is composed of calc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lamprey
Lampreys (sometimes inaccurately called lamprey eels) are an ancient extant lineage of jawless fish of the order Petromyzontiformes , placed in the superclass Cyclostomata. The adult lamprey may be characterized by a toothed, funnel-like sucking mouth. The common name "lamprey" is probably derived from Latin , which may mean "stone licker" ( "to lick" + "stone"), though the etymology is uncertain. ''Lamprey'' is sometimes seen for the plural form. There are about 38 known extant species of lampreys and five known extinct species. Parasitic carnivorous species are the most well-known, and feed by boring into the flesh of other fish to suck their blood; but only 18 species of lampreys engage in this micropredatory lifestyle. Of the 18 carnivorous species, nine migrate from saltwater to freshwater to breed (some of them also have freshwater populations), and nine live exclusively in freshwater. All non-carnivorous forms are freshwater species. Adults of the non-carnivorous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annelid
The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecologies – some in marine environments as distinct as tidal zones and hydrothermal vents, others in fresh water, and yet others in moist terrestrial environments. The Annelids are bilaterally symmetrical, triploblastic, coelomate, invertebrate organisms. They also have parapodia for locomotion. Most textbooks still use the traditional division into polychaetes (almost all marine), oligochaetes (which include earthworms) and leech-like species. Cladistic research since 1997 has radically changed this scheme, viewing leeches as a sub-group of oligochaetes and oligochaetes as a sub-group of polychaetes. In addition, the Pogonophora, Echiura and Sipuncula, previously regarded as separate phyla, are now regarded as sub-groups of polycha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echinoderm
An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea lilies or "stone lilies". Adult echinoderms are found on the sea bed at every ocean depth, from the intertidal zone to the abyssal zone. The phylum contains about 7,000 living species, making it the second-largest grouping of deuterostomes, after the chordates. Echinoderms are the largest entirely marine phylum. The first definitive echinoderms appeared near the start of the Cambrian. The echinoderms are important both ecologically and geologically. Ecologically, there are few other groupings so abundant in the biotic desert of the deep sea, as well as shallower oceans. Most echinoderms are able to reproduce asexually and regenerate tissue, organs, and limbs; in some cases, they can undergo complete regeneration from a single limb. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lumbricidae
The Lumbricidae are a family of earthworms. About 33 lumbricid species have become naturalized around the world, but the bulk of the species are in the Holarctic region: from Canada (e.g. ''Bimastos lawrenceae'' on Vancouver Island) and the United States (e.g. ''Eisenoides carolinensis'', ''Eisenoides lonnbergi'' and most ''Bimastos'' spp.) and throughout Eurasia to Japan (e.g. ''Eisenia japonica'', ''E. koreana'' and ''Helodrilus hachiojii''). An enigmatic species in Tasmania is ''Eophila eti''. Currently, 670 valid species and subspecies in about 42 genera are recognized. This family includes the majority of earthworm species well known to Europeans. Genera The family consists of the following genera: * ''Allolobophora'' Eisen, 1874 * '' Alpodinaridella'' Mršić, 1987 * ''Aporrectodea'' Orley, 1885 * ''Bimastos'' Moore, 1893 * '' Castellodrilus'' Qiu & Bouché, 1998 stat. nov. * '' Cataladrilus'' Qiu & Bouché, 1998 * '' Cernosvitovia'' Omodeo, 1956 * '' Creinella'' Mrši ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megascolecidae
The Megascolecidae is a taxonomic family of earthworms which is native to Madagascar, Australia, New Zealand and both South East Asia and North America. All species of Megascolecidae belong to the Clitellata class. Megascolecidae are a large family of earthworms and they can grow up to 2 meters in length. The intercontinental distribution of Megascolecidae helps in favouring the Continental Drift theory.Reynolds, J.W. 1995. The distribution of earthworms (Annelida, Oligochaeta) in North America. Pp. 133- 153 In: Mishra, P.C., N. Behera, B.K. Senapati and B.C. Guru (eds.). Advances in Ecology and Environmental Sciences. New Delhi: Ashish Publishing House, 651 pp. The distinctive feature that differs Megascolecidae from other earthworm families is their large size in comparison with other earthworm families. They are an essential part of maintaining soil structure, minor carbon sequestration, and maintaining terrestrial ecosystem balance. Megascolecidae is one of many families Anne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
