1. Small intestine by Dr.mohamed abdul-alameer

2. 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.

3. 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 .

4. 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).

5. 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.

6. duodenum

8. function of the brunner gland???

9. jujenum

11. 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.

12. ileum

13. villi