Question

8.  Outline the major events occurring during the digestion and absorption of carbohydrates. Begin with starch digestion in the mouth and end with absorption of monosaccharides in the intestinal capillaries.

Answer 1

Digestion and absorption of carbohydrates

1. The digestion of carbohydrates is start with the mouth which includes both mechanical and chemical digestion.

2. When we chew the food then it is known as mastication in which the food is crumble in to smaller and smaller pieces.

3. The salivary glands secretes the saliva in the oral cavity that coats the food particles. Salivary amylase is contained by the saliva.

4. Salivary amylase breaks the bonds between the monomeric sugar units of disaccharide, oligosaccharides and starch.

5. After that salivary amylase breaks down amylose and amylopectin into the smaller chains of glucose which is known as mextrins and maltose.

6. When the amount of maltose is increases in the mouth then the chemical and mechanical breakdown of starch in whole grain is enhanced with sweetness and then only 5 per cent of starched are broke down in the mouth.

7. After that when Carbohydrates reached to the stomach then there is no chemical breakdown takes place because the function of amylase enzyme does not work due to acidic conditions of stomach.

8. Mechanical breakdown takes place in stomach and the strong peristaltic contraction of the stomach mix the carbohydrates into the more uniform mixture of chyme.

9. The chyme is now expelled into the upper part of the small intestine. When chyme enters into the small intestine then pancreas released the pancreatic juice through the duct.

10. Then, the pancreatic juice help to breakdown the dextrins into the smaller and smaller carbohydrates chain with the help of pancreatic amylase. The enzyme are secreted by the villi.

11. When the carbohydrates are broken down chemically into single sugar units then these enzymes are transported into the inside of intestinal cells.

Absorption of carbohydrates

1. The absorption of carbohydrates begins with the breakdown of complex carbohydrates by the help of salivary and gastric enzyme into oligosaccharides.

2. When they are converted into the oligosaccharides then after that they are hydrolyzed into the monosaccharides by the help of specific disaccharides which is located at the brush border enterocyte.

3. Gluco-amylase maltase help to hydrolyzed the starch into the small polymeers.