Anatomy & Organs

Immune system – structure, function & diseases

Immune system

The immune system is the body’s own defense system. Without an immune system, the human body would be defenseless against harmful environmental influences and harmful changes in the body. The immune system is therefore an endogenous mechanism that is vital.

Definition, importance and function of the immune system

The immune system consists of two mechanisms whose task is to fight off pathogens and foreign substances and thus to keep the body healthy. These defense mechanisms are, on the one hand, the specific, i.e. acquired, immune defence, and on the other hand, the non-specific, innate immune defence. These two main systems complement each other in their various functions.

The main function of the immune system is to successfully fight off pathogens and foreign substances that enter the body from outside. In addition, the immune system can recognize and eliminate diseased and altered body cells. One of the body’s reactions to its own immune system is inflammation . They arise when the immune system tries to remove invading foreign substances or damaged body cells.

With some pathogens, the immune system gives the body immunity after successfully combating the harmful substances and thus protects against renewed diseases. In addition, the immune system can kill tumor cells. Sometimes the immune system can react too strongly to certain substances.

Allergies are an example of an excessive immune response to certain substances. Some functions of the immune system are innate. Others are acquired. The immune system is a very complex endogenous system, the functions of which can be impaired and disrupted by many influences. Numerous diseases can be caused by disorders of the immune system.

Disorders & Diseases

The immune system does not always function perfectly. It can happen that there are excessive immune reactions or a reduced immune defense. If there is an excessive immune reaction to certain substances, this can be expressed in allergies.In the case of allergies, the body usually reacts to foreign substances that would not cause any significant defense 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 innate or develop over time. A weakened immune system is more likely to get infections.

Pathogens and foreign substances that enter the body from outside can spread through the body due to the reduced or non-existent 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 defensive reactions, but also recognizes the body’s own cells and structures that are altered or diseased in any way.

For example, an intact immune system can also find and destroy tumor cells. In the worst case, however, in the case of an autoimmune disease, the defense reactions of the immune system 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, it can lead to the development of cancer , for example. The immune system is also responsible for the rejection of transplanted organs.

Internal & external influences

Disorders of the immune system can be attributed to both external and internal influences. A distinction is also made between congenital and acquired immune system disorders. A congenital immune deficiency is based on genetic defects. In the case of a genetic defect, the carriers of the hereditary factors are damaged.As a result, the functioning of the immune system is disturbed. Only one function of the immune system or several functions can be affected by the disorder. Acquired immune disorders are usually based on external influences. Certain diseases, such as HIV infection , can cause a disruption in the immune system.

In addition, the functions of the immune system are significantly influenced by factors such as diet and stress . In the case of an inadequate diet, in which certain minerals or vitamins are only insufficiently or not at all absorbed, the immune system can be significantly disturbed.

Excessive stress factors can also have a negative effect on the immune system. In addition to these external influences, an acquired immune deficiency can also be triggered by endogenous, i.e. internal, factors. The intestinal flora in particular and also the entire physical condition have an influence on the immune system and can weaken it under certain circumstances.

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.