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Medical Term:


Pronunciation: les'i-thin


Traditional term for 1,2-diacyl-sn-glycero-3-phosphocholines or 3-sn-phosphatidylcholines, phospholipids that on hydrolysis yield two fatty acid molecules and a molecule each of glycerophosphoric acid and choline. In some varieties of lecithin, both fatty acids are saturated, others contain only unsaturated acids (oleic, linoleic, or arachidonic acid); in others again, one fatty acid is saturated, the other unsaturated. Lecithins are yellowish or brown waxy substances, readily miscible in water, in which they appear under the microscope as irregular elongated particles known as “myelin forms,” and are found in nervous tissue, especially in the myelin sheaths, in egg yolk, and as essential constituents of animal and vegetable cells.

[G. lekithos, egg yolk]

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