**3. Intestinal absorption**

There are three main mechanisms that are carried out mainly through the apical membrane of the enterocytes.


Prior to intestinal absorption, a process of chemical and mechanical digestion of foods takes place, which begins in the mouth, through chewing and salivary secretion, and continues in the stomach, by mixing food with gastric juice rich in pepsin. In this way, food is converted into substances capable of crossing the epithelial barrier and passing into the blood and lymphatic circulation [2].

At the level of the brush border formed by the intestinal microvilli of the enterocytes, some enzymes are located, which are not released into the intestinal lumen, carrying out there, various specific hydrolytic functions against disaccharides, peptides, and other nutrients.
