Gross and microscopic characterization of the zygomatic salivary gland of the Philippine non-descript dog

The gross and microscopic characteristics of the zygomatic salivary gland of Philippine non-descript dogs. of both sexes were studied in embalmed cadavers and stained tissue sections, respectively. Grossly, the gland was intraorbital in location and irregular in shape with a thick, rounded rostral part and a thin, flattened caudal part. The lateral surface of the gland was distinctly lobulated and thinly encapsulated while the medial surface was flat, smooth and thickly encapsulated. The gland was vascularized by a branch of infraorbital artery, innervated by a branch of buccal nerve, and measured 2.3 - 3.5 cm long, 1.5 - 2.6 cm wide, 0.8 - 1.5 cm thick and weighed 1.54 - 4.71 g. Histologically, the gland showed a well-developed capsule of mostly collagen fibers, interlobular ducts, intralobular ducts without basal striations and branched tubuloalveolar secretory acini. The intercalated ducts were absent. Mucous, mixed with serous demilunes, and serous acini were observed. The mucous and mixed acini were larger and more numerous than the serous acini. Histochemically, the acini reacted strongly positive to mucicarmine, periodic acid-Schiff, and alcian blue pH 2.5 but weakly positive to alcian blue pH 1.0, suggesting the presence of mixed (predominantly neutral and weakly acidic) mucins. Results indicated that the zygomatic gland of the Philippine nondescript dog was a small, irregular, minor, compound, branched, tubuloalveolar, and mixed (chiefly mucous) salivary gland that secreted predominantly neutral and weakly acidic mucins.