- 1. A grainlike particle; a granulation; a minute discrete mass. 2. A very small pill, usually gelatin or sugar coated, containing a drug to be given in a small dose. 3. A colony of the bacterium or fungus causing a disease or simply colonizing the tissues of the patient. In immunocompromised patients the differentiation is difficult. 4. A small particle that can be seen by electron microscopy; contains stored material. [L. granulum, dim. of granum, grain]- α granules large, rodlike, or filamentous granules found in several types of cells, especially platelets where they are the most numerous type of g.; contain secretory proteins, including fibrinogen, fibronectin, fibrospondin, von Willebrand factor (collectively known as adhesive proteins) and other proteins (platelet factor 4, platelet-derived growth factor, coagulation factor V, etc.).- acrosomal g. the single glycoprotein rich g. within an acrosomal vesicle, which results from the coalescence of proacrosomal granules.- alpha g. a g. of an alpha cell that was named as the first of several kinds or because it was acidophilic.- argentaffin granules granules that reduce silver ions from an ammoniac silver nitrate staining solution.- azurophil g. a g. that stains a reddish purple color with an azure dye; such granules are seen in dry smears of certain mature and developing blood cells, and are membrane-bound primary lysosomes containing enzymes. SYN: kappa g..- basophil g. a g. that stains readily with a basic dye.- Bollinger granules 1. relatively small, but frequently microscopically visible, pale yellow or yellow-white granules observed in the granulomatous lesion, or the exudate, in botryomycosis; the granules consist of irregular aggregates or colonizations of Gram-positive cocci, usually staphylococci; 2. term sometimes incorrectly used synonymously with Bollinger bodies.- chromatic g. SYN: chromophil g. (2).- chromophil g. 1. any readily stainable g.; 2. a g. of chromophil (Nissl) substance. SYN: chromatic g..- chromophobe granules granules that do not stain or stain poorly with the ordinary dyes; such granules are present in some cells in the anterior lobe of the pituitary.- Crooke granules lumpy masses of basophilic material in the basophil cells of the anterior lobe of the pituitary, associated with Cushing disease, or following the administration of ACTH.- eosinophil g. a g. that stains with eosin.- glycogen g. glycogen occurring in cells as beta granules which average about 300 Å in diameter, or as alpha granules which are aggregates measuring 900 Å of smaller particles.- iodophil g. a g. that stains brown with iodine; found in many of the polymorphonuclear leukocytes in pneumonia, erysipelas, scarlet fever, and various other acute diseases.- juxtaglomerular granules osmophilic secretory granules present in the juxtaglomerular cells, thought to contain renin.- kappa g. SYN: azurophil g..- keratohyalin granules irregularly shaped basophilic granules in the cells of the stratum granulosum of the epidermis.- Langerhans g. a small tennis racket-shaped membrane-bound g. with characteristic cross-striated internal ultrastructure; first reported in Langerhans cells of the epidermis. SYN: Birbeck g..- metachromatic granules 1. granules that stain a color different from that of the dye used; SEE ALSO: metachromasia. 2. term sometimes used as a synonym for volutin.- mucinogen granules granules that produce mucin, as in cells of the salivary glands and in the gastric and intestinal mucosae.- Neusser granules tiny basophilic granules sometimes observed in an indistinct zone about the nucleus of a leukocyte.- neutrophil g. a g. stainable with the neutral component of stains, e.g., the Romanovsky-type blood stains.- oxyphil g. SYN: acidophil g..- proacrosomal granules small carbohydrate-rich granules appearing in vesicles of the Golgi apparatus of spermatids; they coalesce into a single acrosomal g. contained within an acrosomal vesicle.- prosecretion granules granules in the cytoplasm of a cell indicative of a preliminary step in the formation of a secretory product.- Schüffner granules SYN: Schüffner dots, under dot.- secretory g. a membrane-bound particle, usually protein, formed in the granular endoplasmic reticulum and the Golgi complex.- specific granules the distinctive granules of basophilic, eosinophilic, and neutrophilic leukocytes, as opposed to their nonspecific azurophilic granules.
* * *gran·ule 'gran-(.)yü(ə)l n1 a) a little grain or small particle esp one of a number of particles forming a larger unitb) a small sugar-coated pill2) a clump of actinomycetes in a lesion
* * *gran·ule (granґūl) [L. granulum] 1. a small particle or grain, as the small beadlike masses of tissue formed on the surface of wounds, or the insoluble nonmembranous particles found in cytoplasm. 2. a small pill made from sucrose.
Medical dictionary. 2011.