Histogenesis of Duodenum in Human Fetuses
Bidyarani Yumnam, Aribam Jaishree Devi, N. Saratchandra SinghAbstract
Background:
The duodenum, the first part of the small intestine, has four parts: superior, descending, horizontal, and ascending. It develops during the 4 th week from the caudal foregut, cranial midgut, and splanchnic mesenchyme. Its wall consists of mucosa, submucosa, muscularis externa, and serosa/adventitia. The mucosa contains villi and crypts of Lieberkühn, while the submucosa contains Brunner’s glands and Meissner’s plexus. The muscularis externa has inner circular and outer longitudinal layers with Auerbach’s plexus between them. Duodenum was studied to observe the various histological changes in human fetal duodenum of different gestational weeks (GWs) and to make a comparison of our findings with the available data.
Methodology:
Duodenum from 65 human fetuses of 12–36 GWs were studied histologically by staining with Hematoxylin and Eosin, Masson’s Trichome, Cresyl violet, and Verhoeff’s and Van Gieson stains.
Results:
Villi are well developed at 12 GW. Mucosa is lined by simple columnar epithelium and goblet cells, with patches of stratified and pseudostratified columnar epithelium in sections of 12–15 GW. Crypts of Lieberkuhn are seen as surface invaginations at 12 GW with Paneth cells at its basal area. Primordium of Brunner’s gland is observed around 14 GW, whereas muscularis mucosae appears by 15 GW. Inner circular layer of muscularis externa has the layer of 4–5 cells thickness, whereas the outer longitudinal layer of muscularis externa has an interrupted layer of 1–2 cells thickness at 12 GW. The outer longitudinal muscle appears continuous by 17–20 GW. Myenteric ganglion cells appear pleomorphic by 25 GW. The serosa in 12–15 GW has sections of simple cuboidal to simple low columnar and simple squamous epithelium.
Conclusions:
The development of all structures of duodenum are well recognizable by 12–20 GW, and maturation is completed by 21–36 GW, which is consistent with findings of other authors.