describe the histology of stomach in human alimentary canal ?

Stomach, small intestine and large intestine all together form a alimentary canal in human beings.

Alimentary canal is composed of four fundamental layers:- Serosa, muscularis, submucosa and mucosa. Muscularis layer can consist of longitudinal muscle fiber, circular muscle fiber or oblique muscle fiber.

Esophagus consists of all four fundamental layers, but the upper end of esophagus does not have sero sa instead it has thin tunica adventitia. The upper half of the esophagus contains longitudinal muscle fibre and lower end contains circular muscle fibres. Mucosa contain straitified squamous epithelium instead of columnar epithelium.

Stomach also has all four fundamental layers. Serosa is thin and muscularis layer is well developed with outer longitudinal, middle circular and inner oblique layer. Muscularis layer plays an important role in churning process. There are three gland located below the mucosa :- Mucus cell (secret mucus), Peptic/zymogen cell (secret pepsin) and Oxyntic cell (secret Hydrochloric acid).

Small intestine also consists of all four fundamental   layers . Both serosa and mucosa are modified, serosa contains subserous aerolar connective tissue layer. Submucosa contains brunner's gland in duodenum. Mucus membrane is modified into villi.

Villi is highly supplied with capillaries and lymph vessels, its main role is to increase the surface area for absorption. Crypts of lieberkuhn are located in base of villi. It consists of two type of cells zymogen and argentaffin. All the secretion of intestinal glands are collectively known as Succus entericus.

Large intestine also contain all four fundamental layers. Muscularis mucosa are thin in colon and thick in rectum. Rectum consists of  voluntary muscle fibre. Mucosa contain mucus cells.