Comparative Histomorphological and Histochemical Studies on the Oesophagus of Nile Tilapia Oreochromis niloticus and African Catfish Clarias gariepinus

Figure 10

Scanning electron micrographs of esophageal mucosa of Nile tilapia (Oreochromis niloticus); (a) prominent longitudinal furrows (G) situated in between the longitudinal primary folds (PF). Note the different size of the longitudinal primary folds and the presence of mucous (M) in the longitudinal furrows (×60). (b) Stratified epithelial cells (SEC) on the primary mucosal folds showing secondary longitudinal folds (SF) interrupted with irregular longitudinal and transverse furrows (G). Note the presence of mucous on the surface epithelium (×500). (c) A third layer of the mucosal folds (TF) appeared on the secondary ones. Note the presence of irregular shaped stratified squamous epithelium provided with wavy prominent microridges (MR) (×1500). (d) Oval elevation in between SEC represented the luminal surface of the mucous cells (GC). Note the presence of opening of empty mucous cells in between SEC (arrow heads) (×4.000). Scale bars: (a) 200 um; (b) 50 um; (c) 10 um; and (d) 5 um.

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