pearl formation in mollusca

College Of Bio-Medical Sciences & Hospital |UCBMSH.ORGPearl is a valuable gem known to mankind since ancient times.

In the different parts of the world, the pearl producing bivalves are reared and pearls are produced artificially by introducing some foreign objects between the mantle and shell. Nacre is composed of an organic, horn-like compound called conchiolin, and calcium carbonate (CaCO 3) in the form of the minerals aragonite or calcite. PEARL: Pearls areformed in molluskan bivalves (clams, oysters, mussels) of several species by the secretion of a substance known as nacre around an irritant in the outer tissue (mantle) of the organism, or between the outer tissue and the shell. March 27, 2019 by Uttaranchal (P.G.)

Pearl formation ..... 37 Postoperative care ... Phylum Mollusca Class Bivalvia Subclass Pterimorphia (Suzuki 1985) Order Pterioida (Suzuki 1985) or M~tiloida (Richard 1985) Family Pteriidae The "wing oysters", genus Pteria, are charac- terized by a more elongate shape than Pinctada spp., being longer (anteroposteriorly) than wide (dorsoventrally).

College Of Bio-Medical Sciences & Hospital. Formation of nacre (mother-of-pearl) is a biomineralization process of fundamental scientific as well as industrial importance.However, the dynamics of the formation process is still not understood. But the actual nature and mode of formation of pearl inside the oyster has now been explained scientifically. Uttaranchal (P.G.)
Pearl Formation. In fact, as soon as a foreign object, somehow, enters the body of a bivalve in between the shell and mantle, the mantle immediately gets irritated and at once encloses it like a sac. The pearl is secreted by the mantle as a protective measure against foreign objects like sand particles, parasites, small larvae or any object of organic and inorganic origin. The value of pearl depends upon its size, quality, etc. Pearl Formation by Mollusca. Pearl is a valuable gem which is known to humans since ancient time.

The mantle wall then starts secreting layers of nacre around the foreign object from defence point of view.

The para­sites are recorded to be the larval forms of trematodes (in most cases). cumingii) and P. vulgaris, which grow to a size of 12-15 cm after 3 years of culture.

Uttaranchal (P.G.) Pearl is a valuable gem known to mankind since ancient times. The old ancient Hindu believe, which still persists in common Indians is that the rain drops of “swati nakshatra” when fall inside the open mouth of pearl oyster become converted into pearl. The mantle wall then starts secreting layers of nacre around the foreign object from defense point of view.Thus, mantle wall secretes continuously several layers of nacre around the foreign object and finally pearl is formed.

The pearl, in fact, is of animal origin and produced by certain bivalves of Mollusca. Pearls are calcareous deposits found inside the bodies of molluscs. Here, we use scanning electron microscopy and high spatial resolution ion microprobe depth-profiling to image the full three-dimensional distribution of organic materials around individual …
The value of pearl depends upon its size, quality, etc. These pearl producing marine oysters belong to the genus Pinctada. However, the culture of pearl, its fishing and its commercialization, etc., constitute a separate story. Pearl is of animal origin and is obtained from Pearl oyster belonging to phylum mollusca.

Pearls are calcareous deposits found inside the bodies of molluscs. College Of Bio-Medical Sciences & Hospital

These pearl producing marine oysters belong to the genus Pinctada. Pearl is produced by black lip pearl oyster or pearl oyster, Pinctada margaritifera ( var.

Formation of Pearl: Pearl is secreted by the mantle as a pro­tection against foreign objects, usually the parasites or coarse sand grains.

Here we are concerned only with the way of the formation of pearl in the body of a bivalve.The pearl is secreted by the mantle as a protective measure against foreign objects like sand particles, parasites, small larvae or any object of organic and inorganic origin. Sometimes a course sand grain may act as a stimulant for the production of a pearl. In fact, as soon as a foreign object, somehow, enters the body of a bivalve in between the shell and mantle, the mantle immediately gets irritated and at once encloses it like a sac.

Thus, mantle wall secretes continuously several layers of nacre around the foreign object and finally pearl is formed. Pearl oysters occur throughout the Indo-Pacific Region. They have been fished for almost two centuries for the mother-of-pearl industry and fine pearls were occasionally harvested from the sea. The pearl producing bivalves are marine oysters of the genus Pinctada, though some freshwater bivalves of the genus Unio and Anodonta also produce pearl but of inferior quality and rarely of any use.Today, Japan produces the bulk of pearl in the world by using pearl culture technique. Now days, the pearl producing bivalves are reared and pearls are produced artificially by introducing some foreign objects between the mantle and shell in the different parts of the world; Japan has surpassed all other countries in this field. College Of Bio-Medical Sciences & Hospital.

Uttaranchal (P.G.) April 3, 2018 by Uttaranchal (P.G.) College Of Bio-Medical Sciences & Hospital |UCBMSH.ORGPearl is a valuable gem which is known to humans since ancient time. The pearl, in fact, is of animal origin and produced by certain bivalves of Mollusca.

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