What is an immune system?
The immune system is a term for the human body’s defense system. This immune system provides protection against internal or external pathogens. The immune system in a human body is located throughout the body such as in the blood, in the intestines, in the skin and in the respiratory tract. This is why, for example, an allergic reaction can manifest itself in the form of fatigue symptoms, as is the case with hay fever, or through skin problems in contact allergy. These symptoms are the result of an immune system that is activated.
A human body’s immune system aims to render foreign substances (seen as a threat) harmless. As a result, it is a defense mechanism for viruses and bacteria. The immune system stores the information from a first specific “attack” and knows exactly how to remove the foreign substances from the body quickly and effectively the next time. This, then, is why a child’s immune system is somewhat weaker (read: informed) and therefore susceptible to specific viruses such as chicken pox is. This also allows us to distinguish between the innate immune system and the acquired immune system.
In the immune system of the human body, a distinction can be made between:
- The physical barrier in the form of the skin but also the mucous membranes in the respiratory tract and in the intestines.
- The general defense that targets all pathogens found in the body. This includes the white blood cells.
- Specific defenses directed against a single pathogen. This involves the use of lymphocytes. Each lymphocyte has only one type of receptor on its cell membrane, which causes the lymphocyte to take action only when the specific pathogen is encountered.