Abstract：
The present study described the full morphology of the duodenum of the Japanese quail during the embryonic stage from 3rd day of incubation till hatching using the light and electron (scanning and transmission) microscope. The specimens were collected, analyzed and described anatomically, morphometrically and microscopically. The first recognition of the prospective duodenum was at the 4th day of incubation and developed continuously by age progression. The prospective duodenum consisted of a flat pseudostratified epithelium, mesenchyme and covering mesothelium. On day 8th of incubation, the epithelium developed three evaginations lead to formation three previllous ridges protruding inside the duodenal lumen, which later at the 9th day differentiated into numbers of projections; villi. On the 9th day, the epithelium lined the villi transformed into a simple columnar type, the duodenal villi appeared as pyramidal-shaped projections, had wide base and narrow apex and by age progression, the duodenal villi went through changes in number, size and shape. On hatching day, the duodenal epithelium consisted of enterocytes interspersed with secretory goblet cells, which stained positive for both Periodic Acid Schiff (PAS) and Alcian blue AB and represented filled with metachromatic granules. The muscular wall started as mesenchymal condensation on the 6th day then differentiated into the circular smooth muscle layer on the 9th day of incubation. Giving detailed information about the morphological development of the duodenum during the incubation period of quail embryo helps in reaching a satisfactory explanation about how the duodenum plays a vital role in digestion, absorption and immunity. HIGHLIGHTS: Studying the quail duodenum can be used as a model for understanding the mammalian duodenum. Understanding the duodenal structure and its function is the best way to maximize the efficiency of the production of the livestock through giving the best type of diet. Duodenum plays a vital role in digestion through the digestible secretions, absorption of nutrients, and immunity against invaders. Duodenum is the spot where the food digestion mostly occurs.
摘要：
本研究使用光和电子（扫描和透射）显微镜描述了日本鹌鹑从孵化第3天到孵化的胚胎阶段十二指肠的完整形态。采集了标本,从解剖学上分析和描述，形态和微观。对预期十二指肠的首次识别是在孵育的第4天，并随着年龄的增长而不断发展。前瞻性十二指肠由扁平的假分层上皮组成，间充质和覆盖间皮。在孵化的第8天，上皮发展了三个逃避导致形成三个前绒毛脊突出在十二指肠腔内，在第9天晚些时候将其区分为许多突起；绒毛。在第九天，绒毛衬里的上皮转变为简单的柱状类型，十二指肠绒毛表现为金字塔形突起，基部宽，顶点窄，按年龄增长，十二指肠绒毛经历了数量的变化，大小和形状。在孵化的那天，十二指肠上皮由肠上皮细胞和分泌杯状细胞组成，高碘酸希夫（PAS）和阿尔辛蓝AB染色均为阳性，并表现为充满异色颗粒。肌壁在第6天开始为间充质凝结，然后在孵育的第9天分化为圆形平滑肌层。提供有关鹌鹑胚胎潜伏期十二指肠形态发育的详细信息，有助于对十二指肠如何在消化中起着至关重要的作用达成令人满意的解释，吸收和免疫。研究鹌鹑十二指肠可以作为理解哺乳动物十二指肠的模型。了解十二指肠结构及其功能是通过提供最佳饮食类型来最大程度地提高牲畜生产效率的最佳方法。十二指肠通过可消化分泌物在消化中起着至关重要的作用，吸收营养，以及对入侵者的豁免权.十二指肠是主要发生食物消化的地方。
