A histological study on the digestive tract of eel ( anguilla anguilla L. ) with special reference to ultrastructure of gastric glandular cells | ||||
| Mansoura Veterinary Medical Journal | ||||
| Article 7, Volume 6, Issue 2, December 2004, Page 85-108 | ||||
| Document Type: Original Articles | ||||
| DOI: 10.21608/mvmj.2004.123297 | ||||
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| Abstract | ||||
| The digestive tracts were obtained from six healthy adult male and female eels, a migrating teleost, the tract was differentiated into oesophagus, stomach and intestine. Specimens from each were processed for light microscopy. Small pieces from gastric mucosa were processed for electron (transmission) microscopic examination of gastric glands. The results revealed a wide structural regional variations in the oesophagus. While, the mucosal lining of its anterior region was formed of stratified squamous epithelium containing taste buds, mucous cells and club (alarm substance) cells, it was replaced by simple columnar secretory epithelium forming serrated outlines at its posterior region. On the other hand, the tunica musculosa was formed of thick striated muscle bundles at the anterior region, which replaced by thick inner circular and thin outer longitudinal smooth muscle bundles at the posterior region. The structure of the gastric wall not showed regional differentiation. It was lined by high columnar cells. The gastric ducts were lined by mucous neck cells. The gastric glands were tubular in shape and lined by dorninant cuboidal cell type. On the basis of ultrastructural features, the gastric glandular cells could be differentiated into oxynticopeptic cells, endocrine cells and basal cells. The intestinal tract showed an excellent regional differentiation. The anterior (respiratory) region was characterized by diminished low cuboidal lining epithelium followed by highly vascular lamina propria containing fine capillary bed well branched and extend to invest the epithelial lining. These features were associated with reduction of tunica musculosa and well-developed vascular serosa. The intestine at the mid-region and at the posterior region showed long mucosal folds and lined by high columnar epithelium containing goblet cells in between. The goblet cells were increased through the lining epithelium of the posterior region (rectum). It can be concluded that, the digestive tract of eel may exert compound functions :taste, digestion as well as respiration (intestinal air breather teleost ) to be adapted to its habita | ||||
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