Title: An Overview of the Small Intestine | histologyolm.stevegallik.org
Headings: An Overview of the Small Intestine
An Overview of the Small Intestine
Basic Histology of the Small Intestine
Image source: diet777.com
Regional Histological Differences

Content: An Overview of the Small Intestine | histologyolm.stevegallik.org
An Overview of the Small Intestine
Image source: A.D.A.M.
The small intestine is the principal site of foodstuff digestion and nutrient absorption along the alimentary canal. It is a relatively long, tubular organ (approximately 6 meters in length) that receives chyme from the stomach through the pyloric outlet and delivers its waste into the cecum of the large intestine. It occupies most of the peritoneal cavity caudal to the stomach. The small intestine is subdivided into three regions. From the proximal to distal ends of the small intestine, these are 1) the duodenum, which is about 25 cm long, 2) the jejunum, which is about 2.5 m long, and 3) the ileum, about 3.5 m long. Basic Histology of the Small Intestine
The mucosa of the small intestine has three generations of permanent folds of its lining surface designed to increase the surface area available for the terminal phases of digestion and absorption: macroscopic, circularly-arranged, submucosal folds, called plicae circulares (valves of Kerckring), smaller mucosal folds, called villi, that cover the folded lumenal surface, and a lining simple striated columnar epithelium that contains absorptive cells (enterocytes), the lumenal surface of which is a highly-folded striated border made up of cellular microvilli. Image source: diet777.com
Intestinal mucosal glands called Crypts of Leiberkuhn are simple, tubular, unbranched glands that empty their contents into the lumen at the base of the villi.