On the skin, in the mouth and pharynx and in the vagina romps only a fraction of the bacteria, the largest part - between 400 and 1000 different kinds - is found in the small and large intestine. The substances produced by the bacteria are used by the intestinal cells. The bacterial flora protects the respective organ against colonization with other, pathogenic germs and additionally often takes on additional functions.
Example skin flora
The bacteria of the skin flora protect the skin from colonization with pathogenic germs, feed on the billions of dander that daily detach from the skin, and also split fats and bactericidal fatty acids, which reduce the growth of other bacteria. Certain areas of the skin are favored by the bacteria: moist areas such as groin bends, underarms and spaces between toes and fingers provide a better climate for most bacteria than dry or calloused skin. A large part of the germs sits in the hair follicles, where they are well protected from external influences have excellent growth conditions.
Example intestinal flora
Although the intestinal flora protects against colonization with pathogenic germs, but their main tasks lie elsewhere: They regulate the located in the intestinal mucosa portions of the immune system, by exercising body defense permanently, and even produce antibiotic substances. They produce vitamins and vitamin precursors such as vitamin K or B 12, thiamine or riboflavin, which are then taken up via the intestinal mucosa. In the metabolic processes of the intestinal flora, substances that can be used by the intestinal cells for energy production accumulate, and the bacteria even provide a certain digestive power and thus help us in food processing.