Licence: Public Domain Mark
Credit: Elements of histology / by E. Klein. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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![Chap. XXIII.] CHAPTER XXIII. THE MOUTH, PHARYNX, AND TONGUE. 250. The glands.—Into the cavity of the mouth and pharynx open very numerous minute glands, which, as regards structure and secretion, are either serous or mucous. The latter occur in the depth of the mucous membrane covering the lips of the mouth, in the buccal mucous membrane, in that of the hard palate, and especially in that of the soft palate and the uvula, in the depth of the mucous membrane of the tonsils, at the back of the tongue, and in the mucous membrane of the pharynx. The serous glands are found m the back of the tongue, in close proximity to the parts containing the special organs for the perception of taste—the taste goblets or buds {see below.) All glands are of very minute size, but when isolated they are perceptible to the unaided eye as minute whitish specks, as big as a pin's head, or bigger. The largest are in the lips, at the back of the tongue and soft palate, where there is something like a grouping of the alveoli around the small branches of the duct, so as to form little lobules. 251, The chief duct generally opens with a narrow mouth on the free surface of the oral cavity; it passes in a vertical or oblique direction through the superficial part of the mucous membrane. In the deeper, looser part (submucous tissue) it branches in two or more small ducts, which take up a number of alveoli. Of course, on the number of minute ducts and alveoli depends the size of the gland. In man, all ducts are lined with a single layer of columnar epithelial cells, longer in the larger than](https://iiif.wellcomecollection.org/image/b21725330_0203.jp2/full/800%2C/0/default.jpg)
