Esophagogastric region and liver tissue in dog-faced water snake Cerberus rynchops : Histology and histochemistry

Structural and Functional Characterization of the Tongue and Digestive Tract ofPsammophis sibilans(Squamata, Lamprophiidae): Adaptive Strategies for Foraging and Feeding Behaviors

“…However, neutral mucopolysaccharides and glycoproteins showed an intense reaction in the central connective tissue core and weak expression at the boundaries of the lining epithelium. In agreement with our records, several reports in the literature noted similar localization for the activity of acid and neutral mucins in the esophagus of P. catenifer (Khamas & Reeves, 2011) and C. rynchops (Boonyoung et al, 2017). Histochemical estimates of collagen localization within the esophagus, using MT staining, further elucidated an intense reaction in the tunica submucosa and the connective tissue of the tunica mucosa.…”

“…Further, in the gastric mucosal glands, shallow and diminutive gastric pits were arranged in the dorsal surface extruding gastric secretions to the stomach lumen. These results agreed with Boonyoung (2017) and Abo-Eleneen et al (2014) whom reported similar distribution for gastric pores in the stomach of C. rynchops and Natrix tessellate , respectively. The gastric glands of P. sibilans were unique in that they possessed large oval-shaped mucous glands at the distal region of mucosa, the isthmus.…”

“…It was thus imperative that the highly folded esophageal mucosal folds, as evidenced by our histological and SEM investigations, played an essential role in the extraordinary esophageal distension when swallowing larger prey. In line with our findings, increased mucosal folding was reported in Pituophis catenifer (Khamas & Reeves, 2011), Mauremys caspica (El-Taib & Jarrar, 1983), Cerberus rynchops (Boonyoung et al, 2017), and Bothrops jararaca and Crotalus durissus (Gogone et al, 2017). Khamas and Reeves (2011) indicated that the mucous secretion of goblet cells facilitates the movement of food items by lubricating the esophageal tract (Ferri et al, 1976).…”

“…Our findings revealed that the esophageal structure was consisted of four successive tunics: the tunica mucosa, submucosa, muscularis, and serosa, as similarly described in other snake species (Khamas & Reeves, 2011; Cundall et al, 2014; Gogone et al, 2017). Also, the mucosa was lined by pseudostratified columnar epithelium interspersed with goblet cells (Khamas & Reeves, 2011; Boonyoung et al, 2017). Notably, the mucosa bears numerous folia toward the luminal space (Abo-Eleneen et al, 2014).…”

“…Squamates have evolved morphological and structural adaptations imposed by dietary specialization (Khamas & Reeves, 2011; Gogone et al, 2017). Several studies have focused on the structure of the gastrointestinal tract in snakes, largely focused on physiological, histochemical, and ecological characterization (Starck & Beese, 2001; Secor, 2003; Khamas & Reeves, 2011; Bessler & Secor, 2012; Cundall et al, 2014; Boonyoung et al, 2017; Gogone et al, 2017). Considering peculiar anatomical features of snake digestive tracts, an interesting study by Helmstetter (2009 a ) illustrated that the snake esophagus joins the stomach directly without hallmarks or an esophageal sphincter, conferring wide space to engulf and consume the prey in its entirety.…”