Question

Describe the anatomy histology and functions of small intestine

Answer 1

1.anatomyMost digestion and absorption of nutrients occur in a long tube called the small intestine. Because of this, its structure is specially adapted for these functions. Its length alone provides a large surface area for digestion and absorption, and that area is further increased by circular folds, villi, and microvilli. The small intestine begins at the pyloric sphincter of the stomach, coils through the central and inferior part of the abdominal cavity, and eventually opens into the large intestin2.duodenumThe first part of the small intestine, the shortest region and is retroperitoneal (behind the peritoneum).3.jejunumis the next portion and is about 1 m (3 ft) long and extends to the ileum. Jejunummeans “empty,” which is how it is found at death. 4.ileumThe terminal, longest part of the small intestine.5.ileocecal sphincterA fold of mucous membrane that guards the opening from the ileum into the large intestine6.histologyThe wall of the small intestine is composed of the same four layers that make up most of the GI tract: mucosa, submucosa, muscularis, and serosa-mucosaThe mucosa is composed of a layer of epithelium, lamina propria, and muscularis mucosae. -absorptive cellsAbsorptive cellsof the epithelium release enzymes that digest food and contain microvilli that absorb nutrients in small intestinal chyme-goblet cellsAlso present in the epithelium are goblet cells, which secrete mucus-intestinal glands or crypts of LieberkuhnThe small intestinal mucosa contains many deep crevices lined with glandular epithelium. Cells lining the crevices form the intestinal glands, secrete intestinal juice.



Answer 2

Answer:

The mucous membrane lining the intestinal wall of the small intestine is thrown into transverse folds called plicae circulares, and in higher vertebrates minute fingerlike projections known as villi project into the cavity. These structures greatly increase the area of the secreting and absorbing surface. It is, on average, 23ft long and is comprised of three structural parts; the duodenum, jejunum and ileum. Functionally, the small intestine is chiefly involved in the digestion and absorption of nutrients. It receives pancreatic secretions and bile through the hepatopancreatic duct which aid with its functions.