Parotid gland

Each acinus is composed of a grapefruit-shaped cluster of serous-producing cells.  Nuclei are peripherally located at the base of the cells; red secretory granules accumulate adjacent to the small central lumen, where they will be released.  The granule contents and their large numbers cause acinar cells to stain intensely.  400x

Each acinus is composed of a grapefruit-shaped cluster of serous-producing cells.  Nuclei are peripherally located at the base of the cells; red secretory granules accumulate adjacent to the small central lumen, where they will be released.  The granule contents and their large numbers cause acinar cells to stain intensely.  400x

Each acinus is composed of a grapefruit-shaped cluster of serous-producing cells.  Nuclei are peripherally located at the base of the cells; red secretory granules accumulate adjacent to the small central lumen, where they will be released.  The granule contents and their large numbers cause acinar cells to stain intensely.  400x

Each acinus is composed of a grapefruit-shaped cluster of serous-producing cells.  Nuclei are peripherally located at the base of the cells; red secretory granules accumulate adjacent to the small central lumen, where they will be released.  The granule contents and their large numbers cause acinar cells to stain intensely.  400x

Secretory product is transported from the acinar lumens into the smallest of the intralobular ducts, the intercalated ducts.  These ducts are lined by simple cuboidal epithelium and are smaller in diameter than surrounding acini.

Intercalated ducts increase in size and anastomose to form another intralobular duct, the striated duct.  Striated ducts are as large as, or larger than, the surrounding acini and display basal striations.  These striations are formed by numerous infoldings of the basal plasma membrane and the many mitochondria that are interposed between the folds.