Histological and Histochemical Studies on the Esophagus, Stomach and Small Intestines of Varanus niloticus

Abstract

Information on the digestive system of the reptiles is based on relatively few studies on some of the now present 7500 reptilian species. Yet, the gap between our understanding of the major similarities and / or differences between the mammalian and reptilian digestive system does not seem satisfiable. The aim of the current study was to investigate the morphological structure of one of the most common reptilian species in Egypt, Varanus niloticus or Nile monitor. Specimens for histological examination were collected from the esophageus, stomach and small intestine of the Nile monitor and pro-cessed for paraffin embedding. Sections were stained with haemat-oxylin and eosin for general morpho-logy. Periodic Acid Schiff's (PAS) and Alcian Blue (AB) staining methods were applied to detect the different types of the mucous contents of the gastro-intestinal tract. Some paraffin sections were stained with Grimelius silver impregnation technique for localization of the enteroendocrine cells.