The immune system is the body's own, individual defense system against harmful pathogens, for example bacteria, parasites, fungi, protozoa (single cell) and viruses. The term 'immune system' is initially only a very inaccurate and includes the entirety of all processes for foreign body defense. 'Immune' (lat. Immunis) means to be protected against certain conditions.
Not only humans have an immune system. Mammals, birds, reptiles, fish and even some microorganisms have their own, albeit less complex, defense system against foreign organisms. This indication speaks for a phylogenetically early establishment.
The Immunobiology Immunology is concerned with the immune system, in which the lymphatic system plays a special role. Immune system responses to extraneous organisms are termed immune responses and are categorized as follows for the first time the organism had defensive capabilities:
Innate immune defense (nonspecific immune reaction)
Acquired immune defense (specific immune reaction)
|Alleged. immune defense||Erworb. immune defense|
|flexibility||low, because genetically determined||High-adaptive|
|components||NK cell, lysozyme, macrophages||antibody|
|reaction||fast and immediate||slowly|
|influence||not possible||additional immunizations through vaccinations possible|
Components of the immune system:
The immune system consists of individual subcomponents, which only form an effective barrier in total. Individually isolated components offer little protection. Only the interaction of all three barriers (see below) leads to a highly effective immune system.
1st barrier = general defense:
Skin: physical barrier to the outside.
Ciliated epithelium: used to clean the respiratory tract.
Gastric acid: the gastric juice (pH = approx. 1) kills microorganisms.
Intestinal flora: colonization resistance against foreign bacterial types.
Lysozyme: Enzyme for the decomposition of microorganisms.
2nd barrier = cellular defense (Cells in the bloodstream and lymph):
Granulocytes: belong to the leukocytes and fight foreign cells.
Lysozyme: decomposition enzyme found in the body secretions.
NK cell: stimulate programmed cell death (apoptosis).
Macrophages: eat possible pathogens via phagocytosis.
T. lymphocyte: partially functioning as memory cells.
3rd barrier = humoral defense (Plasma proteins):
Antibodies: bind to the antigens and render them harmless.
Lysozyme: decomposition enzymes
Interferons: regulate cell growth
The following organs are directly or indirectly involved in the immune system:
appendix: involved in the production of defense cells.
intestine: Main site of the immune system
skin: physical barrier against pathogens of any kind
bone marrow: Synthesis of Lymphocytes, Granulocytes & Monocytes.
lymph node: Filtration of antibodies from the lymphatic fluid.
almonds: is used for the early detection of harmful organisms.
spleen: Filtration of the blood and release of leukocytes
thymus: Conversion of thymocytes into T lymphocytes.
In addition, the body also protects itself through other reactions that we can not consciously control. at fever The body increases the body core temperature and thus worsens the conditions for the pathogens. These usually have only a small tolerance range and denature (structural change of the cell proteins) at elevated temperature.
Also diarrhea and Vomit have their benefit: The body gets rid of the parasite before they can get into the bloodstream. Last also fulfilled one bleedingreaction, e.g. as a result of a cut in the finger, an important function. Possible impurities and bacteria are washed out with the escaping blood.
The body reactions that we perceive as illness, so have their use for the immune system, although not in direct connection.