“Immune system” - the body’s defense

What is the immune system?

Viruses are just as much a part of nature as humans. It is therefore not surprising that we have been given the necessary defense mechanism for our bodies by nature, or more precisely by our Creator. In principle, every higher life form has its own biological defense system that protects it from attacks by bacteria and viruses. The immune system is also able to destroy the body's own cells. However, it only uses this ability to eliminate defective cells.

The immune system is not an independent organ, but rather a complex network and the interaction of various organs, cells and molecules. Without this God-given, endogenous immune system, human health would be at risk, as we are constantly exposed to many dangerous environmental influences. Without this protective function, hostile microorganisms could penetrate our bodies unhindered and damage them. If these invaders are not fought, they cause dysfunctional and sometimes even life-threatening diseases. In addition to bacteria and viruses, there are also fungi and parasites that pose a threat to humans.

How is the immune system structured?

In order to be able to deal with the dangers effectively and safely, the human immune system has various strategies at its disposal. One could also say that the body has set up several lines of defence in order to be able to take further measures immediately after a barrier has been breached. These are mechanical and biochemical barriers,

naturalKiller cells(NK-Cells) whose task is to detect infectedCellsorTumor cellsto recognize and destroy directly. And last but not least Proteine.

Mechanical and biochemical barriers

The first line of defense is formed by mechanical and biochemical protective mechanisms. They are primarily responsible for preventing pathogens from entering the body in the first place. Some of the body's own barriers ensure that the pathogens are quickly removed once they have been intercepted.

Some of these systems are located in the facial area, as sensitive body openings are located there. Both theEyesBoth the oral cavity and the respiratory tract behind it have effective mechanical barriers. Mechanical barriers include the eyelids, lips and nose. Fine hairs in the nose keep foreign substances out and if substances do get into the nose, the body expels them again by sneezing. Biochemical defense mechanisms are also found in the oral cavity. For example, saliva contains the enzyme lysozyme, which is responsible for fighting pathogens.

Cellular structures of the immune system

In addition, the immune system has a variety of cells that fight pathogens even after they have overcome the barriers. These are mainly natural killer cells and T lymphocytes. Some of these cells even combine to form highly specialized systems. This includes the well-known lymphatic system.

If, for example, germs enter the body through an external injury to the skin, it activates the nearest lymph center and produces T lymphocytes. We notice this through the swelling of so-called nodules. This sometimes even hurts a little, but is a good sign because the body's own defense system has gone into action.

However, the cellular components usually circulate in the lymphatic system andblood vesselsof the body and thus reach the different tissue structures. They are mainly formed in the human bone marrow. Each defense cell is specialized in a specific threat to the body. Among other things, the cytotoxic T cells are able to destroy a pathologically altered cell.

The proteins of the immune system

The body also uses proteins as messenger substances in the course of a defense reaction. Medicine refers to these as humoral components. This term is derived from the word "humor," which in a medical context is used synonymously with the term "fluid."

In contrast to the defense cells, these components are not able to move to another location on their own. They simply circulate passively in the bloodstream and lymphatic system to support the defense cells in fighting a pathogen. Among other things, the body's plasma cells produce tailor-made antibodies that attach themselves to the invader and thereby deactivate it.

How does the immune system work?

The mechanical and biochemical barriers offer the body the most effective protection against numerous pathogens. Overall, they prevent over 99 percent of all viruses, bacteria, fungi and parasites from entering the body and thus prevent infection. Only a few pathogens are able to overcome the barriers of the immune system on their own. Most pathogens only enter the human body through a damaged or weakened barrier.

After they have overcome this, the body initiates an immune reaction. It primarily distinguishes between a primary infection and a secondary infection. If it is a primary infection, the immune system initially only reacts with antigen-presenting cells. These can recognize the typical characteristics of a pathogen and enclose it within themselves. This is why medicine often refers to them as phagocytes. After the phagocytes have completely destroyed the pathogen, they present its individual parts on their surface to the lymphocytes, thereby activating them.

The activated lymphocytes then fight the pathogen with aggressive substances and begin producing antibodies. After all invaders have been successfully fought, so-called memory cells remain in the immune system. These contain all the data collected about the pathogen and thus enable a much faster response in the event of a second infection.

What are autoimmune diseases?

At aAutoimmune diseasethe destructive power of the immune system is directed against the body itself. A healthy immune system is able to distinguish between harmless and dangerous cells. In the case of allergies as well as autoimmune diseases, however, the immune system's tolerance fails, so that it then also turns against harmless organisms.

For this reason, the body's own cells are viewed as pathogens and attacked by the immune system. This leads to inflammation and reactive tissue regeneration. In many cases, permanent damage to the affected organ also occurs. In Germany, an average of five percent of people suffer from an autoimmune disease. The most common diseases are:

• psoriasis
• Graves' disease
• Rheumatoid arthritis
• Crohn's disease
• Alopecia Areata