The immune system is the body’s own defense system. Without the immune system, the human body would be defenselessly exposed to harmful environmental influences and harmful changes in the body. Thus, the immune system is an endogenous mechanism that is vital to life.
Definition, importance, and function of the immune system
Plasma cells are cells of the immune system and are used to produce and form antibodies. Orange: plasma cells, white: antibodies. Click to enlarge. The immune system consists of two mechanisms whose function is to fight off pathogens and foreign substances to maintain the health of the body. These defense mechanisms are on the one hand the specific, i.e. acquired immune defense, and on the other hand the non-specific, as innate immune defense. These two main systems complement each other in their various functions. The main function of the immune system is to successfully ward off pathogens and foreign substances entering the body from the outside. In addition, the immune system can recognize and also eliminate diseased and altered body cells. One of the body’s reactions to its own immune defenses is inflammation. They occur when the immune system tries to remove invaded foreign substances or damaged body cells. In the case of some pathogens, the immune system confers immunity on the body after successfully combating the harmful substances, thus protecting against renewed illness. In addition, the immune system can kill tumor cells. Sometimes, however, the immune system can react too strongly to certain substances. Allergies are an example of an excessive immune response to certain substances. Some immune system functions are innate. Others are acquired. The immune system is a very complex endogenous system, which can be impaired and disturbed in its functions by many influences. Numerous diseases can result from disorders of the immune system.
Disorders and diseases
The immune system does not always function completely free of disturbances. It can happen that there are excessive immune reactions or also a reduced immune defense. If an excessive immune reaction to certain substances occurs, this can be expressed in allergies. In the case of allergies, the body usually reacts to foreign substances that would not cause any significant immune reactions in a normally functioning immune system. If there are reduced or no immune reactions at all, this manifests itself in so-called immune deficiency diseases. A weakened immune system can either be congenital or develop over time. With a weakened immune system, infections occur more frequently. Pathogens and foreign substances that enter the body from the outside can spread through the body due to the reduced or completely absent reactions of the immune system. Another disorder in the immune system can manifest itself in the so-called autoimmune diseases. A normally functioning immune system not only reacts to foreign substances with defense reactions, but also recognizes the body’s own cells and structures, which are altered or pathological in some way. For example, an intact immune system can also find and destroy tumor cells. In the case of an autoimmune disease, however, in the worst case the immune system’s defense reactions are directed at healthy endogenous cells and destroy them. It is also possible that the recognition of altered endogenous structures is disturbed. In this case, for example, cancer may develop. The immune system is also responsible for the rejection of transplanted organs.
Internal and external influences
Disorders of the immune system can be attributed to both external and internal influences. In addition, a distinction is made between congenital and acquired immune system disorders. Congenital immune deficiency is based on genetic defects. In the case of a genetic defect, the carriers of the genetic material are damaged. As a result, the functioning of the immune system is disturbed. Only one function of the immune system or several functions may be affected by the disorder. Acquired immune disorders are usually based on external influences. For example, certain diseases such as HIV infection can cause a disorder in the immune system. In addition, the functions of the immune system are influenced to a considerable extent by factors such as diet or even stress.In the case of a deficient diet, in which certain minerals or vitamins are inadequately absorbed or not absorbed at all, the immune defense can be significantly impaired. Excessive stress factors can also have a negative effect on the immune defense. In addition to these external influences, an acquired immune deficiency can also be triggered by endogenous, i.e. internal, factors. Thus, specifically the intestinal flora and also the entire physical condition has an impact on the immune system and can weaken it under certain circumstances.
