Title: Digestive system – Histology
Headings: 12
Digestive system

12 Digestive system
Four layers of digestive tract walls
Mucosa
Submucosa
Muscularis externa
Adventitia
Regional histology of the digestive tract
Esophagus
Stomach
Small intestine
Large intestine
Region
Histological characteristics
Esophagus
Stomach
Small Intestine
Large Intestine

Content: Simple columnar epithelium of the stomach at very high magnification. The stomach epithelium invaginates to form multiple gastric pits. At the bottom of each gastric pits lie gastric glands that reach deep into the lamina propria. Gastric glands produce stomach acid, pepsinogen, and mucus that are then secreted into gastric pits. Figure 7: Gastric glands and gastric pits of gastric mucosa. Small intestine
The small intestine is a long tube that extends from the stomach to the junction with the large intestine (a.k.a colon.) The major functions of the small intestine are digestion, secretion, and absorption. The small intestine is divided into three segments: duodenum,
jejunum
ileum.