The appendix is the beginning of the colon, which begins blindly in the right lower abdomen. The appendix is quite short in humans and measures only about 10 cm. At its side the small intestine and the large intestine are connected.
The blind end merges into a narrow tail-shaped extension, the so-called appendix. This small appendix is often erroneously called the appendix in colloquial speech. The function of the appendix is by no means limited to digestion. It also plays an important role in the intestinal immune system.
Tasks for the digestion
For digestion, the appendix is of little importance compared to the other parts of the intestine. The nutrients from the food were already absorbed in the small intestine in front of it. In the large intestine the main task is the reabsorption of water from the stool and its thickening.
At the same time, electrolytes, especially sodium and potassium, are also reabsorbed by the body. As the appendix is much larger in herbivores, it is assumed that the appendix plays a prominent role in the digestion of fibre-rich food. These otherwise indigestible food components, such as cellulose, are broken down by bacteria and made usable for the body.
Furthermore, the large intestine produces mucus to facilitate the transport of the last remaining food. This transport is further supported by the intestinal movements. In contrast to the small intestine, the entire large intestine, including the appendix, is colonised by a large number of bacteria. These bacteria decompose the last food leftovers that could not be utilized by the body, which can lead to gas formation.
Tasks for the immune system
The appendix and especially its appendix are interspersed with lymphatic tissue whose main function is to defend the immune system. They are therefore the guardians between the large intestine colon colonised by bacteria and the sterile small intestine. The appendix is also called “intestinal tonsil” because it is so richly interspersed with lymphatic tissue.
This lymphatic tissue is also called intestinal associated lymphatic tissue and fulfils important tasks. First, it produces an antibody secretion that protects the intestinal mucosa from microorganisms by cross-linking them with each other. This prevents these microorganisms from attaching themselves to the intestinal cells and penetrating them.
Furthermore, the intestinal mucosa contains so-called M-cells, which transport antigens from the intestinal contents to the cells of our immune system. This enables an immune response of our body, which is very specifically directed against the pathogens. A further aspect of the appendix is possibly a reservoir function for intestinal bacteria, so that a healthy intestinal flora can be restored more quickly after intestinal diseases.
Original function of the appendix
As already mentioned, the appendix is differently pronounced in different animals. In carnivores it is hardly developed and also in humans, who are omnivores, the appendix is quite small. In herbivores, on the other hand, it is very well developed and has a large capacity, especially in herbivores that cannot ruminate.
Ruminanting is important for the digestion of plant fibres. In herbivores that cannot ruminate, these plant fibres must be broken down in the appendix so that the animal can absorb and utilise them. These animals then form a kind of fermentation chamber in which the food is fermented and processed.
One of the animals in which this process is important is the horse. The human being is not dependent on the digestion of fibre-rich food for his food supply, but obtains his energy from other food sources which are easier to digest and are accessible to the body with less energy expenditure. Therefore he is not dependent on the appendix.
In the course of evolution and due to changes in the human diet, the appendix was no longer strained. As a result of this, the appendix has regressed or not developed over time. This process of evolution is a normal adaptation process and can also be observed in other organs or parts of the body.
Thus the coccyx is the remnant of a tail. In addition to the digestion of fibre-rich plant components, which humans can hardly digest today, the appendix appendix in particular still has a role in the immune system. The appendix still has this role today.
However, this function can be compensated by the body if the appendix has been removed after an inflammation. This is because there are also cells of the immune system in the other parts of the intestine. However, people in the western world today are hardly exposed to dangerous intestinal diseases. It is conceivable that the lymphatic tissue of the appendix is of great importance in fighting such a disease.