TY - CHAP M1 - Book, Section TI - Chapter 381. Normal Structure and Function of the Gastrointestinal Tract A1 - Mayer, Alan N. A2 - Rudolph, Colin D. A2 - Rudolph, Abraham M. A2 - Lister, George E. A2 - First, Lewis R. A2 - Gershon, Anne A. PY - 2011 T2 - Rudolph's Pediatrics, 22e AB - The gastrointestinal (GI) tract is a continuous tube beginning at the mouth and ending at the anus (Fig. 381-1). Its main function is to digest food and absorb nutrients and fluid. It is subdivided into 4 regions: (1) esophagus, (2) stomach, (3) small intestine, and (4) large intestine. The liver and pancreas directly communicate with the GI tract via ducts that join with the duodenum, the most anterior segment of small intestine. At the cellular level, the tissue architecture of the gut tube is similar throughout, consisting of 4 concentric layers.1 From inner to outer they are (1) mucosa, (2) submucosa, (3) muscularis propria (externa), and (4) adventitia or serosa. The mucosa is composed of epithelium, lamina propria, and muscularis mucosae (Fig. 381-2). SN - PB - The McGraw-Hill Companies CY - New York, NY Y2 - 2024/03/28 UR - accesspediatrics.mhmedical.com/content.aspx?aid=7035433 ER -