digestive system mouth and stomach

digestive system video about mouth and stomach. Small and big intestine. Digestion system is very very important for all living forms.

small intestine - another organ of digestion system

More than 6 meters of small intestine 

The small intestine is a long tube with a diameter or contour between 3.5 and 5 centimeters, which retreated on himself inside yourself, below the stomach. If you extend your computer's small intestine, measured about 6.7 meters long - as 22 notebooks lined one after another! 

The small intestine plays an important role in breaking down the mix of food from the stomach even more, so your body can absorb all the nutrients it contains vitamins, minerals, proteins, carbohydrates and fats. The roast chicken contains many proteins - and a little fat - and the small intestine will help you absorb them, as long as their friends - the pancreas, liver and gall bladder - you throw a hand. 

The bodies just mentioned various juices to send the first portion of the small intestine. These juices help to digest food and allow the body to absorb the nutrients they contain. The pancreas produces some juices that help the body to digest fats and proteins. Which secretes a juice called bile, the liver helps to absorb fats in the bloodstream. And the gallbladder is like a store bile, which stores this juice to your body when you need it. 

The foods you eat can stay for up to 4 hours in your small intestine until it becomes a liquid mixture and watery. It is a time well spent, because at the end of the trip, nutrients from the pizza, chicken, oranges and milk may move from the intestine into the blood. Once in the blood, your body will be much closer to harness the complex carbohydrates in the body of the pizza, the vitamin C of oranges, chicken protein and calcium from milk.

Parts of Small Intestine

1. Duodenum. The major distinguishing feature of this C-shaped first part of the small intestine is the presence of duodenal (Brunner's) glands in the submucosa. The mucous cells of these glands produce an alkaline secretion. It protects the duodenal lining from the acidity of the chyme and raises the luminal pH to the optimum level for pancreatic enzyme activity. It is also the point of entry for the bile and pancreatic ducts, which penetrate the full thickness of the duodenal wall. It typically exhibits fingerlike or leaflike villi and relatively few goblet cells.

2. Jejunum. An intraperitoneal organ, the jejunum has long leaflike vilii, many plicae circulares, and an intermediate number of goblet cells. The key to its identification, however, is that although it has villi (and is thus part of the small intestine), it contains neither Brunner's glands nor Peyer's patches.

3. Ileum. This intraperitoneal organ has fewer villi, which are short and broad-tipped (clublike), and relatively abundant goblet cells.

Small Intestine Properties

1. Villi. The presence of these epithelium-covered fingerlike mucosal projections into the lumen is the most diagnostic feature of small intestine structure. The villi increase the mucosal surface area about 10-fold and thus enhance absorption; their shape and abundance differ according to the region where they are located.
2. Intestinal glands (crypts of Lieberkuhn), These simple tubular glands (often coiled) extend into the lamina propria below the bases of the villi. They are lined by absorptive, goblet, Paneth's, enteroendocrine, and undifferentiated cells. Their secretions enter the lumen via small openings between the villi. Similar glands are seen in the large intestine, where they contain many more goblet cells.
3. Enterocytes (absorptive cells). These are the predominant cell type covering the villi. They occur in small numbers in the crypts. The approximately 3000 microvilli per cell give the cell-lumen border a striped appearance, referred to as a striated border.

4. Goblet cells. These lie between the absorptive cells, with more in the surface epithelium than in the crypts. They gradually increase in number from the duodenum to the ileum.

5. Paneth's cells. Lying in the bases of the crypts, these cells synthesize a protein polysaccharide complex. In addition to RER and Golgi complexes, they have many large acidophilic secretory granules that contain lysozyme, an antibacterial enzyme that may help control the intestinal flora.

6. Enteroendocrine cells. Most known types of enteroendocrine cells are found in the crypts of the small intestine. Those that occur mainly in this area produce hormones and amines such as secretin, which increases pancreatic and biliary bicarbonate and water secre tion; cholecystokinin, which increases pancreatic enzyme secretion and gallbladder contraction; gastric inhibitory peptide, which decreases gastric acid production; and motilin, which increases gut motility.

7. Undifferentiated cells. Mucosal epithelial cells undergo continual turnover. Replacement occurs through the mitosis of undifferentiated (stem) cells located near the base of the crypts. Products of these divisions differentiate into all the cell types described above; by a mechanism that is still unclear, they move toward the crypt base or toward the tips of the villi, from which they are finally sloughed into the lumen.

SMALL INTESTINE

The small intestine, which includes the duodenum, jejunum, and ileum, receives chyme from the stomach, bile from the liver, and digestive enzymes from the pancreas. Here, nutrients are hydrolyzed into an absorbable form; they are absorbed and transferred to blood and lymphatic capillaries. Undigested material is moved to the large intestine by peristalsis. The word small refers to diameter, not length: the small intestine is longer and narrower than the large intestine.
A. General Structure: The walls of the small intestine have the same layers as do the rest of the tract. A series of permanent folds, the plicae circulares (valves of Kerckring), composed of both submucosa and mucosa, extend into the lumen and increase the surface area about 3-fold. The main distinguishing features of the small intestine (as viewed through the microscope) are in the composition and organization of the mucosa.

B. Mucosa of the Small Intestine: This consists of simple columnar epithelium with goblet cells, underlain by a lamina propria and separated from the submucosa by a muscularis mucosae.