Fine Structure of the Parotid and Mandibular Glands of the Cotton Rat (Sigmodon hispidus)

The parotid and mandibular glands of the cotton rat were examined by light and transmission electron microscopy. Parotid gland: Acinar cells were serous in nature, and contained electron-dense granules. Intercalated duct cells contained electron-dense granules. Striated duct cells had small granules of moderate and high electron densities. Mandibular gland: Acinar cells were seromucous in nature, and contained granules of low and moderate electron densities. Intercalated duct cells contained granules of moderate and high electron densities. Striated ducts were comprised of two portions - a secretory portion and a striated portion without granules. The secretory portion had many electron-dense granules. A sexual dimorphism was obserbed in these granules, which were smaller and fewer in females than in males.