Comparative Histological Study of the Stomach in Two Species of Iraqi Vertebrates (Magpie Pica pica L. and Small Asian Mongoose Herpestes javanicus E.)

Al –Nakeeb Et Al

doi:10.21123/bsj.16.2.0281

Abstract

A histological study showed the wall of the stomach in Pica pica and Herpestes javanicus consists of four layers: mucosa, submucosa, muscularis externa and serosa. Also, the present study showed many differences in the histological structures of the stomach for each in both types. The stomach of P. pica consists of two portions: the proventiculus and gizzard, while the stomach of H. javanicus consists of three portions: cardiac, fundic and pyloric regions. The mucosa layer formed short gastric folds, named plicae. In the proventiculus of P. pica, sulcus is found between each two plicae, but the folds called gastric pits in the gizzard, which are full with koilin. Lamina properia in both types contained gastric glands (straight simple tubular glands) named superficial glands, as well as another gastric gland found in the submucosa layer of the proventiculus in P. pica only named deep gastric glands. The gastric gland in the stomach of H. javanicus contained: mucous neck cells and parietal cells positive to AB/PAS stains in cardiac portion, as well as chief cells in fundic portion, but pyloric portion had just mucous neck cells. Muscularis externa in both types formed two muscle layers: inner and outer layer.

Highlights

The stomach is a large part of the gastrointestinal tract, in mammals and birds, and is responsible for storing and transporting food to the duodenum (1)
The height of cells vary in length, appearing shorter in the base part of the fold than in the top, all of them based on the basement membrane and the lamina properia is composed of loose connective tissue which is rich in blood vessels as well as the presence of gastric glands, which showed a positive response to Alcian blue (AB)/Periodic Acid- Schiff (PAS) stain, which opens in the lumen of stomach (Fig.1A,B,C)
The mucosa of the gizzard consists of simple columnar epithelium which forms short folds, with gastric pits found between each two folds (Fig.4A)

Summary

Introduction

The stomach is a large part of the gastrointestinal tract, in mammals and birds, and is responsible for storing and transporting food to the duodenum (1). The stomach is composed of four layers: the mucosa, submucosa, muscularis, and serosa (2). The mucosa consists of simple columnar epithelium, and a number of gastric glands, which meet with stomach lumen through gastric pits. The layer of submucosa composed of connective tissue, blood and lymph vessels, while the muscularis layer consists of smooth muscles, and the layer of serosa, which appear as thin layer, covers the stomach from the outside (2). The parts of the stomach in birds differ from those of mammals. The bird's stomach is characterized by two parts: the glandular part called proventiculus and muscular part known of gizzard (3). Especially predatory birds, the proventiculus expands and secretes gastric juice during food passage and the gizzard, in some birds serves as teeth, stores the food, digestion and pushing the extract food into the intestines (4)

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Conclusion