The Normal Salivary Glands
1 THE NORMAL SALIVARY GLANDS The salivary gland system is composed of This text focuses on the salivary glands proper exocrine glandular tissue arranged as three but recognizes the relationship to the airway paired, large aggregations, known collectively seromucous glands. as the major salivary glands, and numerous, The basic structure of a salivary gland tissue nonuniformly distributed, small aggregations in is a branching tubule or duct that has the princi- the mucosa of the oral cavity, referred to as the pal secretory cells, the acinar cells, at the ends of minor salivary glands. The major salivary glands the branches and an opening into the oral cavity are the parotid, submandibular (submaxillary), at the other end of a single collecting duct. The and sublingual glands. The major and minor basic salivary gland unit has morphologically and salivary glands produce the fuids that consti- functionally varying segments: acinus, intercalated tute oral saliva. All salivary glands share a basic duct, striated duct, and excretory duct (fg. 1-1). structure, but there are site-specifc variations in These segments have a bilayered cellular compo- function, secretions, and gross and microscopic sition of luminal cells and abluminal peripheral features that infuence the frequency and types cells. The abluminal cells are identifiable as of associated neoplasms. myoepithelial cells in the distal portion of the The seromucous glands of the nasal cavity, gland (acinus and intercalated duct) and basal pharynx, larynx, and bronchi are morpholog- cells in the proximal portion of the gland (ex- ically and functionally similar to many of the cretory duct). There are two types of acinar cells, oral minor salivary glands but, strictly speaking, serous and mucous, whose secretions differ; the are not salivary glands because they do not proportion of each cell type varies by anatomic contribute to the saliva.
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