Chapter 25.5, Problem 4AYLO

Summary Introduction

To discuss:

Histology of the intestinal villi and crypts; the cell types found in each, and their respective functions; the relationship of the lacteal to the lymphatic system, and its function.

Introduction:

The small intestine lies between the stomach and the large intestine. The small intestine consists of three parts—the jejunum, the duodenum, and ileum. It aids in digestion and absorption of ingested food. The tissue layers of the small intestine are similar to the layers of the esophagus and the stomach. Simple columnar epithelial cells line the lumen. The externa possesses a thick circular layer inside. The jejunum and ileum are covered with serosa on all sides, but in the case of duodenal serosa, it is seen only on the anterior surface.