Tales from the crypts: regulatory peptides and cytokines in gastrointestinal homeostasis and disease
Juanita L. Merchant
Juanita L. Merchant
Published January 2, 2007
Citation Information: J Clin Invest. 2007;117(1):6-12. https://doi.org/10.1172/JCI30974.
View: Text | PDF
Review Series

Tales from the crypts: regulatory peptides and cytokines in gastrointestinal homeostasis and disease

Abstract

The gastrointestinal (GI) tract is composed of a diverse set of organs that together receive extracorporeal nutrition and convert it to energy substrates and cellular building blocks. In the process, it must sort through all that we ingest and discriminate what is useable from what is not, and having done that, it discards what is “junk.” To accomplish these many and varied tasks, the GI tract relies on endogenous enteric hormones produced by enteroendocrine cells and the enteric nervous system. In many instances, the mediators of these tasks are small peptides that home to the CNS and accessory gut organs to coordinate oral intake with digestive secretions. As the contents of ingested material can contain harmful agents, the gut is armed with an extensive immune system. A breach of the epithelial barrier of the GI tract can result in local and eventually systemic disease if the gut does not mount an aggressive immune response.

Authors

Juanita L. Merchant

×

Figure 1

Overview of the GI tract.

Options: View larger image (or click on image) Download as PowerPoint
Overview of the GI tract. In humans, the GI tract is a 20-foot muscular ...
In humans, the GI tract is a 20-foot muscular tube lined with primarily endodermally derived columnar epithelial cells. The esophagus begins at the end of the posterior pharynx. The esophagus courses through the thoracic cavity and pierces the diaphragm, where it enters the abdominal cavity and merges with the stomach. The stomach merges distally with the small intestine, which is divided into 3 parts, the duodenum, jejunum, and ileum. The terminal ileum joins the colon at the ileocecal valve. The colon begins in the right lower abdomen (ascending colon) and transverses under the liver into the transverse, then left, colon. Just before entering the rectum, the distal left colon forms an S shape (the sigmoid colon). The luminal GI tract ends at the anus. The liver, pancreas, and gallbladder are accessory organs that form as appendages from the second portion of the duodenum.