Small intestine by Dr.mohamed abdul-alameer

Th e small intestine is a convoluted tube about 5 to 7 meters long Th e small intestine is a convoluted tube about 5 to 7 meters long. For descriptive purposes, the small intestine is divided into three parts:the duodenum, jejunum, and ileum. Characteristic feature of small intestine: 1-the plicae circulares are permanent spiral folds or elevations of the mucosa. 2-Villi: are permanent fingerlike projections of lamina propria of the mucosa. They are covered by simple columnar epithelium.

Layers of small intestine: Mucosa. Submucosa. Muscular layer Layers of small intestine: Mucosa. Submucosa. Muscular layer. serosa(if the tissue is intraperitoneal) / Adventitia (if the tissue is retroperitoneal). Regional differences in small intestine: 1-duodenum: villi are abroad,tall and numerous with fewer goblet cells.there is brunner gland. 2-jujenum:the villi are are tall and lined by simple columnar epi.more goblet cell than duodenum. no gland or lymphatic nodule .

3-ileum: the villi are scant and are narrow and short 3-ileum: the villi are scant and are narrow and short. More goblet cell than both duodenum or jujenum. There are peyers patches (lymphatic aggregates).

Intestinal cell: 1-absorptive cell 2-goblet cell: are interspersed among absorptive cell. 3-Enteroendocrine or APUD (amine precursor uptake and decarboxylation) cells are scattered throughout the epithelium of the villi and intestinal glands. 4-paneth cell: at the base of intestinal glands. they are characterized by deep staining and eosinophilic granules in the cytoplasm.

duodenum

function of the brunner gland???

jujenum

Function of paneth cell: 1-secrete lysozyme(anti-bacterial) 2-phagocytic action. Function of APUD cell: 1-secret regulatory hormone A-gastric inhibitory hormone: inhibit HCL secretion by parietal cell in stomach. B-secretin: enterance of acid into duodenum cause the release of secretin;which then affect the exocrine cell of pancreas that secret bicarbonate. C-cholecystokinin: increase secretion of pancreatic enzyme and induce gall bladder contractility.

ileum

villi