Digestion

There is a process during which, in the digestive tract, food material polymers are broken down into absorbable compounds by the action of digestive tract enzymes. It starts in the mouth, with the action of saliva, and ends in the large intestine. Proteins are hydrolyzed into amino acids, polysaccharides into monosaccharides, fats and glycerols into fatty acids. Digestion can be divided into luminal (digestion in the intestinal lumen) and membranous, occurring on the surface of enterocyte membranes. It is believed that more than 80% of peptide and glycosidic bonds and about 60% of lipids are hydrolyzed on the intestinal cell membranes, as their surface area is large. Gaps between the villi of the small intestine are so small (0.1-0.2 mm) that intestinal microorganisms cannot enter there. Thus, membranous digestion occurs in a sterile environment (see Digestion of Individual Food Compounds).

Source | Glossary of Most Commonly Used Biomedical Terms and Concepts | Lithuanian University of Health Sciences | Academician Professor Antanas Praškevičius, Professor Laima Ivanovienė