THE ORAL CAVITY. 



253 



the fungiform papillae. The motor nerves of the tongue terminate 

 in motor endings. 



GLANDS OF THE ORAL CAVITY. 



The glands of the oral cavity comprise numerous branched 

 tubulo-alveolar glands situated in the mucosa and submucosa of 

 the lips, cheek, and tongue; branched tubular glands in the region 

 of the circumvallate papillae; of a pair of compound branched 

 alveolar glands, the parotid ; and of two pairs of compound 

 branched tubulo-alveolar glands, the submaxillary and sublingual. 

 These are classified according to their secretions into those secret- 

 ing principally mucus (human sublingual and many of the smaller 

 oral glands), and known as mucous glands ; those secreting a fluid 

 albuminoid substance containing no mucus, the serous glands 

 (parotid glands and the small glands near the circumvallate papillae) ; 



Fig. 197. The area designated by a in the previous illustration, shown by a higher 

 magnification; \' about 150: a, Leucocytes in the epithelium; b, one of the spaces 

 in the epithelium filled with leucocytes and more or less changed epithelial cells ; c, 

 blood-vessel ; d, normal epithelium ; e, basal cell of the same. 



and those having a mixed secretion, mucous and serous glands 

 (human submaxillary). The ducts of all these glands open into 

 the cavity of the mouth. The ducts of the smaller oral glands are, 

 as a rule, short and pass up through the mucosa and the epithelium 

 to open on the free surface. The principal excretory ducts of the 

 large salivary glands are Steno's ducts (Stenson's ducts), passing 

 from the parotid glands to the mouth ; Wharton's ducts, the ducts 

 of the submaxillary glands, and Bartholin's ducts for the sublingual 

 glands. The salivary glands consist of numerous lobules and 

 small lobes of glandular tissue, surrounded by a thin fibrous- 

 tissue capsule which sends septa and trabeculae between the lobules 

 and lobes. The duct of each gland on reaching the gland divides 

 into smaller ducts, which penetrate the gland between the lobes and 

 lobules, dividing and redividing in their course; the terminal 



