Histomorphometrical study of the submandibular gland ductal system in the rat.

The duct system of murine submandibular gland is composed, in contrast with other mammals, by four types of ducts, among which the granular duct is unique for rodents. The granular duct shows a typical secretory structure with a clear intersex morphological diversity on which we carried out a morphometrical study in order to determine the relative area of each duct in rats in comparison with the rest of ducts and the whole gland. Our results, in both sexes, show that the duct with the broadest surface is the granular duct, followed by the excretory, striated and the intercalated ducts. In addition, we found a significant intersex difference between the relative surface of the granular and the excretory ducts, being bigger in males than in females. Finally, in both sexes, there is a greater variation in the data related to the excretory ducts than to the other ducts.