Morphohistogenesis of oesophagus in fowl (Gallus domesticus)

Oesophagus extended from pharynx to pro-ventriculus in right side of the ne ck. It had 2 parts, pre-crop and post-crop. The pre-crop part was longer (9 .80-65.00 mm) and wider(1.72-14.00 mm) than the post-crop (7.70-50.00 mm) a nd(1.68-13.20 mm) in all the age groups. The CS area pre-crop was more than post-crop in all the age groups except groups 8 and 10 where it was more i n post-crop. The growth spurt of length and width of both the parts reveale d maximum (85.18 and 46.66%, 132.55 and 90.40%) increase in groups 3-4 and 2-3 respectively. However, CS area revealed maximum and minimum values of g rowth spurt in groups 4 onward. The overall mean thickness of the wall of post-crop part (1201.40 mu m) was more than that of the pre-crop (1172.80 mu m) The tunica mucosa of both th e parts of oesophagus on an average contributed approximately double (46.40 -67.49%) than tunica muscularis (29.00-44.59%). The epithelium changed from simple cuboidal (group 2) to stratified squamous (group 4). The villi and oesophageal glands appeared in group 3. In groups 4 onward, the cells of th e superficial layer of epithelium in post-crop part were keratinized. Howev er, keratinization was not conspicuous in pre-crop. The tubuloalveolar muco us glands in post-crop were profuse in the mucosal folds in contrast to uni formly distributed in the pre-crop.