Final answer:
Carbohydrate digestion in the small intestine involves brush border enzymes such as maltase, sucrase, and lactase. These enzymes break down disaccharides into monosaccharides like glucose, fructose, and galactose, which are then absorbed into the bloodstream.
Step-by-step explanation:
Brush Border Enzymes for Carbohydrate Digestion
The carbohydrate digestion process involves multiple enzymes that work in different compartments of the digestive system. Initially, the enzyme salivary amylase found in saliva starts breaking down carbohydrates into maltose. Afterwards, in the small intestine particularly in the duodenum, pancreatic amylase secreted by the pancreas continues this process by transforming starch and glycogen into maltose.
Ultimately, specific brush border enzymes located on the surface of the intestinal walls take over. These enzymes are essential for breaking down disaccharides into monosaccharides. Maltase breaks down maltose into two glucose molecules. Sucrase splits sucrose (table sugar) into glucose and fructose, and lactase breaks down lactose (milk sugar) into glucose and galactose. These monosaccharides are then absorbed into the bloodstream where they can be utilized for energy.
The presence of secretin in the process stimulates the secretion of sodium bicarbonate in the small intestine, which helps to provide an ideal pH for the functioning of these enzymes.
For those who are lactose intolerant, insufficient lactase leads to difficulty in digesting lactose found in dairy products. Other complex carbohydrates and fibrous polysaccharides such as cellulose are not digested and provide dietary fiber that aids in digestion.