Bhatia Anmol, Shatanof Rachel A., Bordoni Bruno
A.T.Still University-School of Osteopathic Med
Florida International University Hebert Wertheim College of Medicine; Dartmouth College
The purpose of this article is to give an introduction of the gastrointestinal system, provide an outline of basic embryology, summarize the embryological events that take place with the gastrointestinal tract, and finally provide specific tests that can be utilized to detect GI anomalies. The gastrointestinal (GI) system involves three germinal layers: mesoderm, endoderm, ectoderm. 1. Mesoderm gives rise to the connective tissue, including the wall of the gut tube and the smooth muscle. 2. Endoderm is the source of the epithelial lining of the gastrointestinal tract, liver, gallbladder, pancreas. 3. Ectoderm further separates into the surface ectoderm, neural tube, and neural crest. The surface ectoderm is the precursor to the epidermis, lens of eyes, nails, hair. The neural tube differentiates into the brain and spinal cord. The neural crest is the source of the peripheral nervous system, including the neurons of the GI tract (also called the enteric nervous system). The gastrointestinal system has the divisions: the foregut, midgut, and hindgut. The foregut (or anterior gut) is from the oral cavity to the initial part of the duodenum. The midgut is from the mid-duodenum to the initial two-thirds of the transverse colon. The hindgut is from the later one-third transverse colon to the upper portion of the anus. The three sections of the GI tract have different blood supplies; the foregut receives vascular supply by the celiac artery, the superior mesentery artery supplies the midgut, and the hindgut gets its supply from the inferior mesentery artery.
本文旨在介绍胃肠道系统，概述基本胚胎学，总结胃肠道发生的胚胎学事件，并最终提供可用于检测胃肠道异常的特定检测方法。胃肠道系统涉及三个胚层：中胚层、内胚层、外胚层。1. 中胚层产生结缔组织，包括肠管壁和平滑肌。2. 内胚层是胃肠道、肝脏、胆囊、胰腺上皮内衬的来源。3. 外胚层进一步分化为表面外胚层、神经管和神经嵴。表面外胚层是表皮、眼球晶状体、指甲、毛发的前体。神经管分化为脑和脊髓。神经嵴是周围神经系统的来源，包括胃肠道的神经元（也称为肠神经系统）。胃肠道系统分为：前肠、中肠和后肠。前肠（或前端肠）从口腔至十二指肠起始部。中肠从十二指肠中部至横结肠的前三分之二。后肠从横结肠的后三分之一至肛门上部。胃肠道的这三个部分有不同的血液供应；前肠由腹腔动脉供血，中肠由肠系膜上动脉供血，后肠由肠系膜下动脉供血。
