Describe the digestion of carbohydrates.

Digestion of carbohydrates :

Carbohydrates are a major part of our food. They include polysaccharides, disaccharides and monosaccharides. 

1. Digestion in buccal cavity : In buccal cavity food is mixed with saliva secreted by salivary glands. The saliva contains ptyalin. Ptyalin converts starch into sugar (maltose, isomaltose and limit dextrin)

2. Digestion in stomach : In stomach the saliva continues to act on food for about 30 minutes but the action of HCl stops the action of saliva.

3. Digestion in duodenum : As the food called chyme comes from stomach into duodenum immediately pancreatic juice secreated by pancreas under the influence of secretin hormone (secreated by enteric epithelium of duodenum) comes into duodenum. The pancreatic juice contains pancreatic amylase whcih converts starch into maltose, isomaltose and limit dextrin.

Digestion of carbohydrates in jejunum-ileum : As chyle comes from duodenum into ileum the intestinal juice secreted by intestinal glands gets mixed with the food. The intestinal juice carry out the reactions :

Maltose space rightwards arrow with Malltase on top Glucose space plus Glucose space

Lactose space rightwards arrow with Lactase on top Glucose space plus Galactose

Sucrose space rightwards arrow with Sucrase space on top Glucose space plus space Fructose. space