Even if it sounds strange: Digestion already begins in the mouth. There, the enzymes contained in saliva do a rough preliminary work. Chew for a while on whole-grain bread – it suddenly tastes sweet because enzymes break down starch into sugar. Later, the stomach uses its acid to break down proteins and emulsify fats. Through the “gatekeeper,” the food mush passes from the stomach into the small intestine. The small intestine is divided into three parts: Duodenum (“duodenum”), jejunum and ileum. It winds through the abdominal cavity for a total of about five meters. The small intestine is where the actual absorption and utilization of food components takes place. The individual components – molecules such as glucose, fats or even vital minerals such as potassium and calcium – now enter the blood via the intestinal mucosa and can thus reach the entire organism.
Large surface area of the intestine
To be able to cope with this onslaught at all, nature has come up with something clever. As a result, the surface area of the small intestine is immensely increased, as the mucous membrane is laid down in so-called villi and folds. Folds are distinct elevations with a “connective tissue base,” villi are small finger-shaped mucosal protrusions.
The duodenum is where the ducts from the liver and pancreas open out, and their digestive juices work their magic in the small intestine. The bile acids of the liver are important for fat digestion, and the various enzymes of the pancreas further break down proteins, as well as fats and carbohydrates.
The colon and rectum are the final sections of the digestive tract. In the colon, water and electrolytes are removed from the indigestible remains of the food pulp and returned to the body. In addition, bacteria, for example lactobacilli and Escherichia coli, settle in the colon. The bacteria are important for normal intestinal activity, further break down indigestible remains, and also produce vitamins that are vital for us.
