https://wiki-pathfindersonline.designerthan.at/api.php?action=feedcontributions&feedformat=atom&user=200.56.74.20 2026-05-03T14:54:17Z User contributions MediaWiki 1.35.5 https://wiki-pathfindersonline.designerthan.at/index.php?title=AY_Honors/Shells_-_Advanced/Answer_Key&diff=17363 2006-10-25T03:55:47Z

<p>200.56.74.20: </p> <hr /> <div>The '''mantle''' is an organ found in [[mollusk]]s. It is the dorsal body wall covering the main body, or visceral mass. The [[Epidermis (skin)|epidermis]] of this organ secretes [[calcium carbonate]] to create a shell. <br /> <br /> == Shell formation ==<br /> <br /> [[Nacre]] is secreted by the [[germ layer|ectodermic]] [[cell (biology)|cells]] of the mantle tissue of most mollusks. Mollusk [[blood]] is rich in a liquid form of [[calcium]]. In these mollusks the calcium is concentrated out from the blood where it can crystallize as calcium carbonate (CaCO&lt;sub&gt;3&lt;/sub&gt;). The individual crystals of each layer differ in shape and orientation. Nacre is continually deposited onto the inner surface of the animal's [[animal shell|shell]] (the [[iridescent]] ''nacreous layer'', also known as ''[[Nacre|mother of pearl]]''), both as a means to smoothen the shell itself and as a defense against [[parasite|parasitic organisms]] and damaging detritus.<br /> <br /> The calcium carbonate layers are generally of two types: an outer, chalk-like prismatic layer and an inner pearly, lamellar or nacreous layer. The layers may incorporate a substance called [[conchiolin]], often in order to help bind the calcium carbonate crystals together. Conchiolin is composed largely of [[quinone]]-tanned [[protein]]s.<br /> <br /> Some shells may also contain pigments, which accounts for the fabulous colours of some [[seashell]]s. These shell pigments may include compounds like [[pyrrole]]s and [[porphyrin]]s, which are also proteins.<br /> <br /> == The mantle cavity ==<br /> A mantle skirt is a double fold of mantle that encloses a water space. This space is called the ''mantle cavity'', and it is a central feature of mollusk biology, containing the mollusk's [[gill]]s, [[anus]], [[osphradium]], [[nephridiopore]]s, and [[gonopore]]s. The mantle cavity may function as a [[Respiration (physiology)|respiratory]] chamber (all mollusks), feeding structure ([[bivalve]]s), brood chamber (several forms), or locomotory organ ([[cephalopod]]s and some bivalves).<br /> <br /> The mantle is highly muscular. In cephalopods it is used to force water through a tubular siphon, the [[hyponome]], to propel the animal quickly through the water. In other mollusks, it is used as a kind of &quot;foot&quot; for locomotion.<br /> <br /> The [[nervous system]] of cephalopods is the most complex of the [[invertebrate]]s. The giant [[nerve]] fibers of the cephalopod mantle have been a favorite experimental material of [[Neurophysiology|neurophysiologists]] for many years.<br /> <br /> == See also ==<br /> * [[Aperture (mollusc)|Aperture]]<br /> * [[Columnella]]<br /> * [[Operculum (gastropod)|Operculum]]<br /> <br /> [[Category:Animal anatomy]]<br /> [[Category:Molluscs]]<br /> <br /> [[pt:Manto (molusco)]]<br /> [[ru:Мантия моллюсков]]</div>

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