Abstract
The fine structure of the duct systems (intercalated, striated and main excretory duct) of the Japanese monkey, Macaca fuscata, submandibular gland was observed by transmission electron microscopy.
The intercalated duct epithelium was composed of cuboidal cells. Many low electron-dense large granules (400-800 nm in diameter) were observed in the supranuclear cytoplasm. There were abundant free ribosomes, sacks of rough endoplasmic reticulum and well-developed Golgi apparatus in the cytoplasm. Myoepithelial cells were found within the basal lamina at the periphery of the intercalated ducts. The cytoplasm of the myoepithelial cell was occupied by small myofibrils consisting of bundles of myofilaments.
The striated duct epithelium was composed of columnar cells with basal infoldings. Many vesicles, which contain amorphous substances similar to that seen in the lumen, were present in the apical cytoplasm of the striated duct cells close to the intercalated duct epithelium. Many moderately electron-dense small granules (140-250 nm in diameter) were present in the apical cytoplasm of the striated duct cell. Both types of striated duct cells had coated pits and coated vesicles just beneath the luminal surface. They were also seen at the basal side. The fine structure was very similar to that of the rat submandibular and parotid glands.
The main excretory duct (MED) epithelium was pseudostratified and composed of light cells of Types I and II, goblet cells and basal cells. There were well-developed interdigitations between the light cells.
Tuft cells and dark cells, which were obsereved in the MED epithelium of the rat submandibular gland, were not present in that of the Japanese monkey.
