PHYSIOL 1 Lecture Notes - Lecture 19: Active Transport, Renal Glucose Reabsorption, Brush Border
Document Summary
In order to absorb the larger carbohydrates, polysaccharides must be broken down into monosaccharides. Digestion of carbohydrates begins in the mouth with the salivary enzyme amylase. This enzyme breaks up the large polysaccharides into smaller polysaccharides and maltose. Once the food reaches the stomach, the digestion of the carbohydrates essentially stops because of the acidic environment which denatures the salivary amylase. When the food reaches the small intestine, digestion of carbohydrates begins because the pancreas secretes amylase into the duodenum. The pancreas also secretes bicarbonate ions which neutralize the acid from the stomach. The neutralized environment permits pancreatic amylase to perform digestive function. The pancreatic amylase digests the polysaccharide starch to the disaccharide maltose. Each disaccharide requires a specific enzyme to break it down to monosaccharides. These enzymes are located in the brush border of the microvilli located on the intestinal epithelial cells. Lactase breaks down lactose to galactose and glucose. Maltase breaks down maltose to two glucose monosaccharides.
