File Name: digestion and absorption of carbohydrates .zip
Digestion is the chemical breakdown of the ingested food into absorbable molecules. Absorption refers to the movement of nutrients, water and electrolytes from the lumen of the small intestine into the cell, then into the blood.
Digesting or metabolizing carbohydrates breaks foods down into sugars, which are also called saccharides. These molecules begin digesting in the mouth and continue through the body to be used for anything from normal cell functioning to cell growth and repair. There are three main types of carbohydrates.
The primary site of carbohydrate digestion is in the lumen of the small intestine, where pancreatic amylase begins the digestion of starch granules amylose and amylopectin. In some birds, there is some salivary amylase action in the mouth, but not in farm animals. Dietary simple sugars, such as glucose and fructose, do not need to be digested, as they can be absorbed through the intestinal epithelium directly. The end products of starch digestion diffuse into the brush border, where the final digestive processes occur. Disaccharides such as maltase and isomaltase on the intestinal brush border then complete the degradation and are hydrolyzed to their constituent monosaccharides by enzymes on the brush border, and the monosaccharides released are absorbed into the enterocyte. Sucrose is acted upon by sucrase to yield glucose and fructose for absorption. In young animals kept on milk preweaning , lactose is acted upon by lactase to yield glucose and galactose.
The mechanical and chemical digestion of carbohydrates begins in the mouth. Chewing, also known as mastication, crumbles the carbohydrate foods into smaller and smaller pieces. The salivary glands in the oral cavity secrete saliva that coats the food particles. Saliva contains the enzyme, salivary amylase. This enzyme breaks the bonds between the monomeric sugar units of disaccharides, oligosaccharides, and starches. The salivary amylase breaks down amylose and amylopectin into smaller chains of glucose , called dextrins and maltose. The increased concentration of maltose in the mouth that results from the mechanical and chemical breakdown of starches in whole grains is what enhances their sweetness.
Carbohydrates are hydrophilic and require a series of reactions to digest them to monosaccharides which are absorbed in the small intestine. Carbohydrates.
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Imagine taking a bite of pizza. It tastes amazing, but it's also full of fuel for your body, much of it in the form of carbohydrates. What types of carbohydrates would you find in that bite? Lactose from the cheese. Sucrose, glucose, and fructose from the naturally-occurring sugars in the tomatoes, as well as sugar that may have been added to the sauce. Starch in the flour used to make the crust.
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