Most of the useful elements enter the human body through the gastrointestinal tract (GI tract). Before delivering the elements to different body parts – the food we eat, has to be prepared properly. Thus, the digestive function of the GI tract plays a big role in the normal functioning of the body. After being processed mechanically and moistened in our mouth, the food pushes into the stomach and small intestine. Then it is broken down into smaller elements, or nutrients, that are used for the cell construction and energy generation. However, the digestive function is not the only one that the GI tract performs.
Not so many people realize the significance of the protective function of the GI tract. The whole digestive system operates as a natural protective boundary between the external and internal environment of the body. The thing is that together with food, a large amount of foreign substances and bacteria can enter the cavity of the digestive tract. That’s why the GI tract has a multi-stage system of protection, that filters useful elements from useless and harmful.
To protect the body from the harmful foreign macro molecules, the digestive system starts to split them into monomers. This mechanism is mostly controlled by the mucous layer of the GI tract. In addition, the mucous layer neutralizes certain antigens that are contained in these foreign elements.
Three main components
The main components of immunological and non-immunological protection mechanisms are produced in the small intestine. Digestive secrets of the gastrointestinal tract (like saliva, gastric juice, bile) also perform a protective function due to their antibacterial and disinfecting qualities.
Another important function of the GI tract is excretory. To maintain homeostasis of the internal environment, it is necessary to constantly remove metabolic wasted products from the bloodstream. Thus, such metabolic products as urea, uric acid, creatinine are removed through the GI tract.
The excretory function of the digestive tract is regulated by the central nervous system.