RT Book, Section
A1 Cohen, Mitchell B.
A2 Kline, Mark W.
SR Print(0)
ID 1182907108
T1 Normal Structure and Function of the Gastrointestinal Tract
T2 Rudolph's Pediatrics, 23e
YR 2018
FD 2018
PB McGraw-Hill Education
PP New York, NY
SN 9781259588594
LK accesspediatrics.mhmedical.com/content.aspx?aid=1182907108
RD 2024/04/24
AB The  gastrointestinal  (GI)  tract  is  a  continuous  tube  beginning  at  the  mouth  and  ending  at  the  anus  (Fig.  376-1).  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.  The  main  function  of  the  GI  tract  is  to  digest  food  and  absorb  nutrients  and  fluid.  At  the  cellular  level,  the  tissue  architecture  of  the  gut  tube  is  similar  throughout,  consisting  of  4  concentric  layers;  from  the  inner  layer  to  outer  layer,  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.  376-2).