What happens in the small intestine?
The small intestine, which is specifically designed to maximize the digestion and absorption process, has an expanded surface area with inner folds, called plicae, villi and microvilli, to increase its surface area and enhance its ability to absorb nutrients. All together, this surface is called the brush border of the small intestine. Some enzymes are present on the surface of the brush border, such as disaccharidases like sucrase, maltase, and lactose, which hydrolyze disugars (sugars composed of two monosaccharides) to their two individual sugar molecules. The duodenum, the part of the small intestine that is closest to the stomach, is a neutralization chamber in which the chyme from the stomach is mixed with bicarbonate, which appears again, this time in the pancreatic juice. Bicarbonate lessens the chyme’s acidity, thus allowing more enzymes to function and furthering the breakdown of macromolecules still present. The pancreatic juice also contains many of the enzymes necessary fo
