Electron microscopical observations on early sialoliths in a human submaxillary gland

Abstract

Specimens of human submaxillary gland were examined in the electron microscope. The intercalated duct cells were found to be pyramidal in form, and to contain mucous droplets in their apical cytoplasm. The cells are smooth in outline, and lack the membrane specializations commonly associated with ion and water transport. No specific function could be ascribed to these cells. In specimens of submaxillary gland obtained from one patient, early sialoliths were observed in the lumina of some of the intercalated and striated ducts. These sialoliths are composed of two moieties—one crystalline, the other nondashcrystalline. The crystalline component consists of numerous plate-like crystals, which measure 500Å–1500Å in length and about 65Å in thickness and which closely resemble the hydroxyl apatite crystals seen in dentine, enamel and bone. The crystals are disposed in various arrangements in relation to the noncrystalline component, which consists of a finely fibrillar and stippled material. No sites of intracellular calcification were observed.