[Morphometric study of changes in the submandibular gland of aging rats. 2. Ducts].

A decrease in rat submandibular gland parenchyma could be observed with increasing age, consequent to an apparent increase in the proportion of intralobular ducts. Signs of acinar atrophy were noted with nuclei of smaller volume. A great variety of nuclear sizes and shapes was also observed. The blood vessels were smaller, and the connective tissue was increased. These histological data were confirmed in part by application of the technique of Chalkley. The granulous duct cell height is smaller in old animals.