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Chiton Epidermis TEM
Chitons () are marine molluscs of varying size in the class Polyplacophora ( ), formerly known as Amphineura. About 940 extant and 430 fossil species are recognized. They are also sometimes known as sea cradles or coat-of-mail shells or suck-rocks, or more formally as loricates, polyplacophorans, and occasionally as polyplacophores. Chitons have a shell composed of eight separate shell plates or valves. These plates overlap slightly at the front and back edges, and yet articulate well with one another. Because of this, the shell provides protection at the same time as permitting the chiton to flex upward when needed for locomotion over uneven surfaces, and even allows the animal to curl up into a ball when dislodged from rocks. The shell plates are encircled by a skirt known as a girdle. Habitat Chitons live worldwide, from cold waters through to the tropics. They live on hard surfaces, such as on or under rocks, or in rock crevices. Some species live quite high in the int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tonicella Lineata
''Tonicella lineata'', commonly known as the lined chiton, is a species of chiton from the North Pacific. Size and description ''Tonicella lineata'' is a very colorful chiton, having blue, purple or black straight or zig-zag lines on each of the eight valves. The background color of the valves is often brown or red, but can also be bright blue or yellow to orange. The girdle is hairless and brown to red or pink, often with regular yellow or white patches. This species grows to 5 cm in length. Similar species '' Tonicella lokii'' is extremely similar but has radiating bands on the girdle. '' Tonicella undocaerulea'' is very similar but lacks a dark border to the concentric blue lines on the anterior plate. '' Mopalia spectabilis'' looks superficially similar due to its bright blue wavy lines on the valves, but has a hairy girdle.Baldwin, A. (2007). Illustrated Keys to the chitons (Polyplacophora). Accessed from: It can also be confused with '' Tonicella insignis'' ( Reeve, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsum (biology)
Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and axes. The meaning of terms that are used can change depending on whether a vertebrate is a biped or a quadruped, due to the difference in the neuraxis, or if an invertebrate is a non-bilaterian. A non-bilaterian has no anterior or posterior surface for example but can still have a descriptor used such as proximal or distal in relation to a body part that is nearest to, or furthest from its middle. International organisations have determined vocabularies that are often used as standards for subdisciplines of anatomy. For example, '' Terminolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atrium (heart)
The atrium (; : atria) is one of the two Heart#Chambers, upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the Ventricle (heart), heart ventricles through the atrioventricular valve, atrioventricular mitral valve, mitral and tricuspid valve, tricuspid heart valves. There are two atria in the human heart – the left atrium receives blood from the pulmonary circulation, and the right atrium receives blood from the venae cavae of the systemic circulation. During the cardiac cycle, the atria receive blood while relaxed in diastole, then contract in systole to move blood to the ventricles. Each atrium is roughly cube-shaped except for an ear-shaped projection called an atrial appendage, previously known as an auricle. All animals with a closed circulatory system have at least one atrium. The atrium was formerly called the 'auricle'. That term is still used to describe this chamber in some other animals, such as the ''Mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gill
A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are kept moist. The microscopic structure of a gill presents a large surface area to the external environment. Branchia (: branchiae) is the zoologists' name for gills (from Ancient Greek ). With the exception of some aquatic insects, the filaments and lamella (surface anatomy), lamellae (folds) contain blood or Coelom#Coelomic fluid, coelomic fluid, from which gases are exchanged through the thin walls. The blood carries oxygen to other parts of the body. Carbon dioxide passes from the blood through the thin gill tissue into the water. Gills or gill-like organs, located in different parts of the body, are found in various groups of aquatic animals, including Mollusc, molluscs, crustaceans, insects, fish, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anus
In mammals, invertebrates and most fish, the anus (: anuses or ani; from Latin, 'ring' or 'circle') is the external body orifice at the ''exit'' end of the digestive tract (bowel), i.e. the opposite end from the mouth. Its function is to facilitate the defecation, expulsion of wastes that remain after digestion. Bowel contents that pass through the anus include the gaseous flatus and the semi-solid feces, which (depending on the type of animal) include: indigestible matter such as bones, hair pellet (ornithology), pellets, endozoochory, endozoochorous seeds and gastrolith, digestive rocks; Summary at residual food material after the digestible nutrients have been extracted, for example cellulose or lignin; ingested matter which would be toxic if it remained in the digestive tract; excretion, excreted metabolites like bilirubin-containing bile; and dead mucosal epithelia or excess gut bacteria and other endosymbionts. Passage of feces through the anus is typically controlled by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mantle (mollusc)
The mantle (also known by the Latin language, Latin word pallium meaning mantle, robe or cloak, adjective pallial) is a significant part of the anatomy of molluscs: it is the dorsum (biology), dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself. In many species of molluscs the Epidermis (skin), epidermis of the mantle secretes calcium carbonate and conchiolin, and creates a mollusc shell, shell. In sea slugs there is a progressive loss of the shell and the mantle becomes the dorsal surface of the animal. The words mantle and pallium both originally meant ‘cloak’ or ‘cape’; see mantle (vesture). This anatomical structure in molluscs often resembles a cloak because in many groups the edges of the mantle, usually referred to as the ''mantle margin'', extend far beyond the main part of the body, forming flaps, double-layered structures which have been adapted for many different uses, including for e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snail
A snail is a shelled gastropod. The name is most often applied to land snails, terrestrial molluscs, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gastropoda that have a coiled gastropod shell, shell that is large enough for the animal to retract completely into. When the word "snail" is used in this most general sense, it includes not just land snails but also numerous species of sea snails and freshwater snails. Gastropods that naturally lack a shell, or have only an internal shell, are mostly called ''slugs'', and land snails that have only a very small shell (that they cannot retract into) are often called ''semi-slugs''. Snails have considerable human relevance, including Snails as food, as food items, as pests, and as vectors of disease, and their shells are used as decorative objects and are incorporated into jewellery. The snail has also had some cultural significance, tending t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hanleya
''Hanleya'' is a genus of polyplacophoran molluscs known from Oligocene and Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ... fossils; it is represented today by a number of species including '' H. sinica'' Xu 1990 (China), '' H. brachyplax'' (Brazil) and ''H. hanleyi'' Bean in Thorpe, 1844 (Chile), which feeds on sponges. References Prehistoric chiton genera Chiton genera Oligocene genus first appearances Miocene genus extinctions Hanleyidae {{paleo-mollusc-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Engrailed (gene)
''engrailed'' is a homeodomain transcription factor involved in many aspects of multicellular development. First known for its role in arthropod embryological development, working in consort with the Hox genes, ''engrailed'' has been found to be important in other areas of development. It has been identified in many bilaterians, including the arthropods, vertebrates, echinoderms, molluscs, nematodes, brachiopods, and polychaetes. It acts as a "selector" gene, conferring a specific identity to defined areas of the body, and co-ordinating the expression of downstream genes. Protein ''engrailed (en)'' encodes the homeodomain-containing transcription factor protein Engrailed. Homologous Engrailed proteins are found in a diversity of organisms. When expressed in the ectoderm, ''engrailed'' is involved in the production of skeletal material. ''engrailed'', or genes with very similar sequences, are found in all bilaterian animals. ''engrailed'' plays a number of crucial roles in bra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acanthochitona Garnoti
''Acanthochitona garnoti'', the spiny chiton, is a medium-sized chiton, polyplacophoran mollusc in the family (biology), family Acanthochitonidae, found on the coast of southern Africa. Description This species is conspicuous for the nine paired tufts or rosettes of long glassy spines that decorate its girdle (chiton), girdle. Between the tufts, the girdle bears many smaller spicules. The spicules are sharp, and if carelessly handled, easily penetrate the human skin, where they detach and remain, becoming painfully irritating. The valve (mollusc), valves are of a dull brown color and marked with oblique pale stripes. They are largely concealed by the girdle. Adult size is 30–45 mm. Distribution and habitat ''A. garnoti'' occurs along the south coast of Africa, from Cape Columbine in Namibia to the south coast of KwaZulu-Natal in South Africa. It can be found on exposed rock surfaces high up in the inter-tidal zone, a location that is unusually far from the water for chito ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polysaccharides
Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long-chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with water (hydrolysis) using amylase enzymes as catalyst, which produces constituent sugars (monosaccharides or oligosaccharides). They range in structure from linear to highly branched. Examples include storage polysaccharides such as starch, glycogen and galactogen and structural polysaccharides such as hemicellulose and chitin. Polysaccharides are often quite heterogeneous, containing slight modifications of the repeating unit. Depending on the structure, these macromolecules can have distinct properties from their monosaccharide building blocks. They may be amorphous or even insoluble in water. When all the monosaccharides in a polysaccharide are the same type, the polysaccharide is called a homopolysaccharide or homoglycan, but when more t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chiton Shell
Chitons () are marine molluscs of varying size in the class Polyplacophora ( ), formerly known as Amphineura. About 940 extant and 430 fossil species are recognized. They are also sometimes known as sea cradles or coat-of-mail shells or suck-rocks, or more formally as loricates, polyplacophorans, and occasionally as polyplacophores. Chitons have a shell composed of eight separate shell plates or valves. These plates overlap slightly at the front and back edges, and yet articulate well with one another. Because of this, the shell provides protection at the same time as permitting the chiton to flex upward when needed for locomotion over uneven surfaces, and even allows the animal to curl up into a ball when dislodged from rocks. The shell plates are encircled by a skirt known as a girdle. Habitat Chitons live worldwide, from cold waters through to the tropics. They live on hard surfaces, such as on or under rocks, or in rock crevices. Some species live quite high in the int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
