Histogenesis of the reticular groove of the buffalo (Bubalus bubalis) stomach.

Histogenesis of the reticular groove (sulcus reticuli) of the buffalo (Bubalus bubalis) was observed from primordial stage to birth. The epithelium of the reticular groove was considered early embryonic until a crown-rump (CR) length of 2.2 cm, and was uniformly distributed at CR 2.2 cm; superficial and basal zones developed by CR 3.2. cm. At CR 10.5 cm, the basal zone in the floor evaginated and formed longitudinal folds. At CR 25.5 cm, the basal zone in the lipids evaginated and formed papillae. The core of the longitudinal folds and papillae was formed by the lamina propria, muscularis mucosae, and submucosa. Keratinization was seen at CR 50.5 cm, and the epithelium was stratified squamous epithelium with keratinization, similar to that of the adult buffalo. The floor and lip had a single layer of muscle. A small oblique muscle layer was also found in the concavity of the lip. The correlation between structure and function of the reticular groove is discussed.