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Hirudinea
Leeches are segmented parasitic or predatory worms that comprise the subclass Hirudinea within the phylum Annelida. They are closely related to the oligochaetes, which include the earthworm, and like them have soft, muscular segmented bodies that can lengthen and contract. Both groups are hermaphrodites and have a clitellum, but leeches typically differ from the oligochaetes in having suckers at both ends and in having ring markings that do not correspond with their internal segmentation. The body is muscular and relatively solid, and the coelom, the spacious body cavity found in other annelids, is reduced to small channels. The majority of leeches live in freshwater habitats, while some species can be found in terrestrial or marine environments. The best-known species, such as the medicinal leech, ''Hirudo medicinalis'', are hematophagous, attaching themselves to a host with a sucker and feeding on blood, having first secreted the peptide hirudin to prevent the blood from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euhirudinea
Euhirudinea, the true leeches, are an infraclass of the Hirudinea. Taxonomy These clitellate annelids are of somewhat unclear relationships; namely the relationships of Hirudinea with oligochaetes are in need of revision. It may be that the presumed sister taxon of the Euhirudinea, the Acanthobdellidea, turns out to be more distantly related, as was already the case with the Branchiobdellida. Thus, eventually Euhirudinea might become a junior synonym of Hirudinea. True leeches are subdivided into two groups, the Arhynchobdellida or Arhynchobdellae (proboscisless leeches), and the Rhynchobdellida or Rhynchobdellae (jawless leeches). Note that the lack of jaws is a plesiomorphy, while the presence of a proboscis is an apomorphy – not all Arhynchobdellida have jaws, but all Rhynchobdellida have a proboscis. The best-known leech species, ''Hirudo medicinalis ''Hirudo medicinalis'', the European medicinal leech, is one of several species of leeches used as "medicinal leeches ... [...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 polychae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helobdella
''Helobdella'' is a genus of leeches in the family Glossiphoniidae, the freshwater jawless leeches. They occur worldwide.Kutschera, U., et al. (2013)Description of a new leech species from North America, ''Helobdella austinensis'' n. sp.(Hirudinea: Glossiphoniidae), with observations on its feeding behaviour.''Zoosyst Evol'' 89(2) 239-46. These are small, flat leeches which do not feed on blood.Siddall, M. E. and E. Borda. (2003)Phylogeny and revision of the leech genus ''Helobdella'' (Glossiphoniidae) based on mitochondrial gene sequences and morphological data and a special consideration of the ''triserialis'' complex.''Zoologica Scripta'' 32(1), 23-33. Several species in this genus are used as model organisms in the study of developmental biology. It has been difficult to define species in this genus without DNA analysis. Like other leeches in this family, some ''Helobdella'' species are polymorphic, coming in different colors and patterns. On the other hand, some uniformly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hirudo Medicinalis
''Hirudo medicinalis'', the European medicinal leech, is one of several species of leeches used as "medicinal leeches". Other species of ''Hirudo'' sometimes also used as medicinal leeches include '' H. orientalis'', ''H. troctina'', and '' H. verbana''. The Asian medicinal leech includes '' Hirudinaria manillensis'', and the North American medicinal leech is '' Macrobdella decora''. Morphology The general morphology of medicinal leeches follows that of most other leeches. Fully mature adults can be up to 20 cm in length, and are green, brown, or greenish-brown with a darker tone on the dorsal side and a lighter ventral side. The dorsal side also has a thin red stripe. These organisms have two suckers, one at each end, called the anterior and posterior suckers. The posterior is used mainly for leverage, whereas the anterior sucker, consisting of the jaw and teeth, is where the feeding takes place. Medicinal leeches have three jaws (tripartite) that resemble saws, on which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parasitism
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has characterised parasites as "predators that eat prey in units of less than one". Parasites include single-celled protozoans such as the agents of malaria, sleeping sickness, and amoebic dysentery; animals such as hookworms, lice, mosquitoes, and vampire bats; fungi such as honey fungus and the agents of ringworm; and plants such as mistletoe, dodder, and the broomrapes. There are six major parasitic strategies of exploitation of animal hosts, namely parasitic castration, directly transmitted parasitism (by contact), trophicallytransmitted parasitism (by being eaten), vector-transmitted parasitism, parasitoidism, and micropredation. One major axis of classification concerns invasiveness: an endoparasite lives inside the hos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haemadipsa Zeylanica Japonica
''Haemadipsa'' is a genus of leeches, with members commonly known as ''jawed land leeches''. These annelids are known from subtropical and tropical regions around the Indian and Pacific Ocean. Well-known ''Haemadipsa'' are for example the Indian Leech (''Haemadipsa sylvestris'') and the yamabiru or Japanese Mountain Leech (''Haemadipsa zeylanica''). Members of the genus feed on blood. They are troublesome to humans and animals especially because their bites result in prolonged bleeding. Species in the genus ''Haemadipsa'' *'' Haemadipsa cavatuses'' *''Haemadipsa cochiniana'' *''Haemadipsa crenata'' *''Haemadipsa hainana'' *'' Haemadipsa interrupta'' *''Haemadipsa japonica'' *''Haemadipsa limuna'' *''Haemadipsa moorei'' *''Haemadipsa montana'' *''Haemadipsa ornata'' *'' Haemadipsa picta'' (Tiger leech) *''Haemadipsa rjukjuana'' *''Haemadipsa sumatrana'' *''Haemadipsa sylvestris'' (Indian leech) *''Haemadipsa trimaculosa'' *''Haemadipsa zeylanica ''Haemadipsa'' is a genus of leech ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bloodletting
Bloodletting (or blood-letting) is the withdrawal of blood from a patient to prevent or cure illness and disease. Bloodletting, whether by a physician or by leeches, was based on an ancient system of medicine in which blood and other bodily fluids were regarded as "humours" that had to remain in proper balance to maintain health. It is claimed to have been the most common medical practice performed by surgeons from antiquity until the late 19th century, a span of over 2,000 years. In Europe, the practice continued to be relatively common until the end of the 19th century.B.) Anderson, Julie, Emm Barnes, and Enna Shackleton. "The Art of Medicine: Over 2,000 Years of Images and Imagination ardcover" The Art of Medicine: Over 2, 000 Years of Images and Imagination: Julie Anderson, Emm Barnes, Emma Shackleton: : The Ilex Press Limited, 2013. The practice has now been abandoned by modern-style medicine for all except a few very specific medical conditions. In the overwhe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epicondylitis
Epicondylitis is a type of musculoskeletal disorder that refers to an inflammation of an epicondyle. It is caused by repetitive motion. In athletes, it is linked to poor technique. Nonsurgical treatment is effective in approximately 95% of cases. Types include: * Lateral epicondylitis, also known as tennis elbow Tennis elbow, also known as lateral epicondylitis or enthesopathy of the extensor carpi radialis origin, is a condition in which the outer part of the elbow becomes painful and tender. The pain may also extend into the back of the forearm. Onse .... * Medial epicondylitis, also known as golfer's elbow (Also thrower's elbow). References Inflammations {{musculoskeletal-disease-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microsurgery
Microsurgery is a general term for surgery requiring an operating microscope. The most obvious developments have been procedures developed to allow anastomosis of successively smaller blood vessels and nerves (typically 1 mm in diameter) which have allowed transfer of tissue from one part of the body to another and re-attachment of severed parts. Microsurgical techniques are utilized by several specialties today, such as general surgery, ophthalmology, orthopedic surgery, gynecological surgery, otolaryngology, neurosurgery, oral and maxillofacial surgery, plastic surgery, podiatric surgery and pediatric surgery. History Otolaryngologists were the first physicians to use microsurgical techniques. A Swedish otolaryngologist, Carl-Olof Siggesson Nylén (1892–1978), was the father of microsurgery. In 1921, in the University of Stockholm, he built the first surgical microscope, a modified monocular Brinell-Leitz microscope. At first he used it for operations in animals. In No ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anticoagulant
Anticoagulants, commonly known as blood thinners, are chemical substances that prevent or reduce coagulation of blood, prolonging the clotting time. Some of them occur naturally in blood-eating animals such as leeches and mosquitoes, where they help keep the bite area unclotted long enough for the animal to obtain some blood. As a class of medications, anticoagulants are used in therapy for thrombotic disorders. Oral anticoagulants (OACs) are taken by many people in pill or tablet form, and various intravenous anticoagulant dosage forms are used in hospitals. Some anticoagulants are used in medical equipment, such as sample tubes, blood transfusion bags, heart–lung machines, and dialysis equipment. One of the first anticoagulants, warfarin, was initially approved as a rodenticide. Anticoagulants are closely related to antiplatelet drugs and thrombolytic drugs by manipulating the various pathways of blood coagulation. Specifically, antiplatelet drugs inhibit pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silurian
The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozoic Era. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out. One important event in this period was the initial establishment of terrestrial life in what is known as the Silurian-Devonian Terrestrial Revolution: vascular plants emerged from more primitive land plants, dikaryan fungi started expanding and diversifying along with glomeromycotan fungi, and three groups of arthropods ( myriapods, arachnids and hexapods) became fully terrestrialized. A significant evolutionary milestone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
