Tuesday, 5 May 2015

Digestive System




Digestive System
The Mouth
Digestion starts in the mouth where amylase a salivary enzyme breaks down starch in carbohydrates into maltose. Lettuce contains high water content, small amounts of protein, fat and carbohydrates. Tomatoes contain vitamins, fiber and water. Cheese has low levels of carbohydrates, protein and fat. Onions have a fiber known as inulin. Ranch dressing contains lactose and is typically made of buttermilk. The pizza crust contains carbohydrates.
The Stomach
Once in the duodenum, the chyme is mixed with digestive secretions from the liver, pancreas and gallbladder. Amylase from the pancreatic juice further breaks down starch and glycogen into maltose and other disaccharides. Maltases, sucrases and lactases enzymes break the disaccharides to monosaccharides. The monosaccharides are absorbed in the intestinal epithelium to produce energy and are transported through the bloodstream to different cells in the body. Most proteins are digested in the stomach with the help of pepsin that breaks them into peptides. Pepperoni and cheese contain protein components. Other enzymes produced by the pancreas in the duodenum, the trypsin, elastase, and chymotrypsin reduce the proteins to even smaller peptides. Peptidases further break down the peptides into amino acids that are absorbed through the small intestines into the bloodstream. Olive oil helps in production of peptides which aid in absorption of nutrients.
The lingual lipase and gastric lipase aid the digestion of lipids in the stomach. The liver produces bile which helps in digestion of lipids. Vitamins are either lipid-soluble or water-soluble. Water-soluble vitamins can be absorbed directly from the intestines into the bloodstream. The fat-soluble vitamins absorption is similar to lipids

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