Morphological Studies of The Stomach of Malayan Pangolin, Manis javanica

Abstract

The morphology of the stomach of Malayan pangolin, Manis javanica was studied by macroscopic, scanning electron microscopic, histological, histochemical and immunohistochemical methods. The stomach was of a cashew or red-bean shape with short lesser curvature. Instead of the simple columnar epithelium, almost the entire luminal stomach was lined by keratinized stratified squamous epithelium, except the pyloric gland region. Asymmetrical sphincter-like shape was detected in the esophageal junction. The gastric gland consisted of mucous, oxyntic, and pyloric glands. Mucous glands were clustered in three regions of the stomach: the median of the lesser curvature, around the duct orifice of the oxyntic gland, and the pyloric antrum regions. The mucous glands were lobulated and each lobe had a duct orifice. The glands consisted of mucous type cells which were rather cuboidal in shape with an oval or spherical basally located nucleus and endocrine cells. Oxyntic glands gathered to form a big glandular mass located in the median greater curvature. The gland consisted of mucous surface epithelium, mucous neck cells, parietal cells, chief cells and endocrine cells. The gland drained into the stomach lumen through a single common duct positioned centrally at the pyloric site. Pyloric gland was located in the most distal portion of the stomach, near the junction of duodenum. The gland consisted of mucous type cells and endocrine cells resembled those of mucous glands. Unlike the other two glands, the pyloric gland was lined by columnar epithelium, as those of common mammals. A big mucosal fold named 'comma shape' covered by numerous hard spines of pyloric teeth, was found in the lesser curvature of the antrum pyloric region. This structure was supported with considerable thickened of muscle layers and contained of small pebbles, indicating that it might serve as a triturating function, similar to the avian's gizzard.