دراسـة لنسيج الأنبوب الهـضمي في سـمكة البـعوض (Baird & Girard) Gambusia affinis البـالغة

Abstract

The adult fishes Gambusia affinis ( Baird & Girard ) were taken from Al-Gazil market in Baghdad and from the small canals at University of Baghdad in Jadriyah district during the period from November 2000 to September 2001. The histological study of the digestive tube showed that: 1) The wall of esophagus was lined by tunica mucosa of lining epithelium represented by stratified squamous epithelial tissue with taste buds at the anterior part only and mucous cells. It is supported by the lamina propria/ tunica submucosa throughout. The esophagus wall was lacked muscularis mucosa due to the confluent of lamina propria and tunica submucosa to form one layer between epithelial tissue and tunica muscularis externa which consisted of two layers of striated muscle fibers, the inner was longitudinal and the outer was circular, which was covered with tunica adventitia at the anterior part (except latero – dorsal region) and tunica serosa at the posterior part. 2) The wall of the intestine was lined by tunica mucosa of lining epithelium represented by simple columnar epithelial tissue with striated border, goblet cells and granular cells, resting on the lamina propria/ tunica submucosa. The intestinal wall also lacked muscularis mucosa due to confluent of lamina propria and tunica submucosa and the formation of lamina propria/ tunica submucosa which lied between epithelial tissue and muscularis externa. The tunica muscularis externa consisted of two layers of visceral muscular fibers, the inner was circular and the outer was longitudinal which was the opposite arrangement to that in esophagus. Muscularis externa was covered with tunica serosa