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Tentacles
In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work mainly like muscular hydrostats. Most forms of tentacles are used for grasping and feeding. Many are sensory organs, variously receptive to touch, vision, or to the smell or taste of particular foods or threats. Examples of such tentacles are the eyestalks of various kinds of snails. Some kinds of tentacles have both sensory and manipulatory functions. A tentacle is similar to a cirrus, but a cirrus is an organ that usually lacks the tentacle's strength, size, flexibility, or sensitivity. A nautilus has cirri, but a squid has tentacles. Invertebrates Molluscs Many molluscs have tentacles of one form or another. The most familiar are those of the pulmonate land snails, which usually have two sets of tentacles on the head: when exte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautilus
A nautilus (; ) is any of the various species within the cephalopod family Nautilidae. This is the sole extant family of the superfamily Nautilaceae and the suborder Nautilina. It comprises nine living species in two genera, the type genus, type of which is the genus ''Nautilus (genus), Nautilus''. Though it more specifically refers to the species ''chambered nautilus, Nautilus pompilius'', the name chambered nautilus is also used for any of the Nautilidae. All are protected under CITES CITES Appendix II, Appendix II. Depending on species, adult shell diameter is between . The Nautilidae, both extant and extinct, are characterized by involute or more or less convoluted shells that are generally smooth, with compressed or depressed whorl (mollusc), whorl sections, straight to sinuous Suture (anatomy), sutures, and a tubular, generally central siphuncle.Kümmel, B. 1964. Nautiloidae-Nautilida, in the Treatise on Invertebrate Paleontology, Geological Society of America and Univ of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giant Squid
The giant squid (''Architeuthis dux'') is a species of deep-ocean dwelling squid A squid (: squid) is a mollusc with an elongated soft body, large eyes, eight cephalopod limb, arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida (though many other molluscs within the broader Neocoleoidea are also ... in the family (biology), family Architeuthidae. It can grow to a tremendous size, offering an example of deep-sea gigantism, abyssal gigantism: recent estimates put the maximum body size at around for females, with males slightly shorter, from the cephalopod fin, posterior fins to the tip of its long cephalopod limb, arms. This makes it longer than the colossal squid at an estimated , but substantially lighter, as it is less robust and its arms make up much of the length. The Mantle (mollusc), mantle of the giant squid is about long (longer for females, shorter for males), and the feeding tentacles of the giant squid, concealed in life, are . Clai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jellyfish
Jellyfish, also known as sea jellies or simply jellies, are the #Life cycle, medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals, although a few are anchored to the seabed by stalks rather than being motile. They are made of an umbrella-shaped main body made of mesoglea, known as the ''bell'', and a collection of trailing tentacles on the underside. Via pulsating contractions, the bell can provide propulsion for animal locomotion, locomotion through open water. The tentacles are armed with cnidocyte, stinging cells and may be used to capture prey or to defend against predators. Jellyfish have a complex biological life cycle, life cycle, and the medusa is normally the sexual phase, which produces planula larvae. These then disperse widely and enter a sedentary #Life cycle, polyp phase which may include asexual budding before reaching sexual maturity. Jellyfish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemoreceptor
A chemoreceptor, also known as chemosensor, is a specialized sensory receptor which transduces a chemical substance ( endogenous or induced) to generate a biological signal. This signal may be in the form of an action potential, if the chemoreceptor is a neuron, or in the form of a neurotransmitter that can activate a nerve fiber if the chemoreceptor is a specialized cell, such as taste receptors, or an internal peripheral chemoreceptor, such as the carotid bodies. In physiology, a chemoreceptor detects changes in the normal environment, such as an increase in blood levels of carbon dioxide (hypercapnia) or a decrease in blood levels of oxygen (hypoxia), and transmits that information to the central nervous system which engages body responses to restore homeostasis. In bacteria, chemoreceptors are essential in the mediation of chemotaxis. Cellular chemoreceptors In prokaryotes Bacteria utilize complex long helical proteins as chemoreceptors, permitting signals to travel lon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cnidarian
Cnidaria ( ) is a phylum under kingdom Animalia containing over 11,000 species of aquatic invertebrates found both in fresh water, freshwater and marine environments (predominantly the latter), including jellyfish, hydroid (zoology), hydroids, sea anemones, corals and some of the smallest marine parasites. Their distinguishing features are an uncentralized nervous system distributed throughout a gelatinous body and the presence of cnidocytes or cnidoblasts, specialized cells with ejectable flagella used mainly for envenomation and capturing prey. Their bodies consist of mesoglea, a non-living, jelly-like substance, sandwiched between two layers of epithelium that are mostly one cell (biology), cell thick. Cnidarians are also some of the few animals that can reproduce both sexually and asexually. Cnidarians mostly have two basic body forms: swimming medusa (biology), medusae and sessility (motility), sessile polyp (zoology), polyps, both of which are radially symmetrical with mou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hole Saw
A hole saw (also styled holesaw), also known as a hole cutter, is a saw blade of annular (ring) shape, whose annular kerf creates a hole in the workpiece without having to cut up the core material. It is used in a drill. Hole saws typically have a pilot drill bit (arbor) at their center to keep the saw teeth from walking. The fact that a hole saw creates the hole without needing to cut up the core often makes it preferable to twist drills or spade drills for relatively large holes (especially those larger than . The same hole can be made faster and using less power. The depth to which a hole saw can cut is limited by the depth of its cup-like shape. Most hole saws have a fairly short aspect ratio of diameter to depth, and they are used to cut through relatively thin workpieces. However, longer aspect ratios are available for applications that warrant them. Common hole saw depths are 38, 45 and 60 mm and for drilling through e.g. (angled-) rooftop constructions also a de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crown Cork
The crown cork (also known as a crown seal, crown cap or just a cap), the first form of bottle cap, was invented by William Painter in 1892 in Baltimore. The company making it was originally called the Bottle Seal Company, but it changed its name with the almost immediate success of the crown cork to the ''Crown Cork and Seal Company''. It still informally goes by that name, but is officially Crown Holdings. Overview A Dutch patent application from 1892 This style of closure is still in widespread use. Prior to the invention of the external crown cork bottle stopper, soda bottles had ordinary internal cork bottle stoppers and often had rounded bottoms so they could not be stored standing upright. Corks have a tendency to dry out and shrink, allowing the gas pressure in the bottle to cause the cork to "pop", so bottles were stored on their side to prevent the corks from drying out. After the invention of the crown cork bottle stopper, this problem was eliminated, and soda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colossal Squid
The colossal squid (''Mesonychoteuthis hamiltoni'') is a species of very large squid belonging to the family Cranchiidae, that of the cockatoo squids or glass squids. It is sometimes called the Antarctic cranch squid or giant squid (not to be confused with the giant squid in genus ''Architeuthis'') and is believed to be the largest squid species in terms of mass. It is the only recognized member of the genus ''Mesonychoteuthis''. The species is confirmed to reach a mass of at least , though the largest specimens—known only from beaks found in sperm whale stomachs—may perhaps weigh as much as , making it the largest extant invertebrate. Maximum total length is ~. Larger estimates exist, however these include the feeding tentacles measured on dead specimens as in life the squid’s tentacles are hidden, only released when capturing prey. If tentacles are considered, lengths of and exist, but the former estimate is more likely.Roper, C.F.E. & P. Jereb (2010). Family Cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Umbrella Term
Hypernymy and hyponymy are the wikt:Wiktionary:Semantic relations, semantic relations between a generic term (''hypernym'') and a more specific term (''hyponym''). The hypernym is also called a ''supertype'', ''umbrella term'', or ''blanket term''. The hyponym names a subset, subtype of the hypernym. The semantic field of the hyponym is included within that of the hypernym. For example, "pigeon", "crow", and "hen" are all hyponyms of "bird" and "animal"; "bird" and "animal" are both hypernyms of "pigeon", "crow", and "hen". A core concept of hyponymy is ''type of'', whereas ''instance of'' is differentiable. For example, for the noun "city", a hyponym (naming a type of city) is "capital city" or "capital", whereas "Paris" and "London" are instances of a city, not types of city. Discussion In linguistics, semantics, general semantics, and ontology components, ontologies, hyponymy () shows the relationship between a generic term (hypernym) and a specific instance of it (hyponym ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peduncle (anatomy)
A peduncle is an elongated stalk of tissue. Sessility is the state of not having a peduncle; a sessile mass or structure lacks a stalk. In medicine, a mass such as a cyst or polyp is said to be ''pedunculated'' if it is supported by a peduncle. There are in total three types of peduncles in the cerebellum of the human brain, known as superior cerebellar peduncle, middle cerebellar peduncle, and inferior cerebellar peduncle. Pedunculated eyes are also the defining attribute of the stylophthalmine trait found in certain fish larvae. The caudal peduncle is a slightly narrowed part of a fish where the caudal fin meets the spine. See also * Peduncle (botany) References Gross pathology {{anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ventral Nerve Cord
The ventral nerve cord is a major structure of the invertebrate central nervous system. It is the functional equivalent of the vertebrate spinal cord. The ventral nerve cord coordinates neural signaling from the brain to the body and vice versa, integrating sensory input and locomotor output. Because arthropods have an open circulatory system, decapitated insects can still walk, groom, and mate — illustrating that the circuitry of the ventral nerve cord is sufficient to perform complex motor programs without brain input. Structure The ventral nerve cord runs down the ventral ("belly", as opposed to back) plane of the organism. It is made of nervous tissue and is connected to the brain. Ventral nerve cord neurons are physically organized into neuromeres that process signals for each body segment. Anterior neuromeres control the anterior body segments, such as the forelegs, and more posterior neuromeres control the posterior body segments, such as the hind legs. Neurom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
