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The immune system

Organs of the human immune system

What is the immune system?

The immune system is a collection of organs, tissues and cells, which are aimed directly at protecting the body from various diseases and the extermination is already trapped in the body of foreign substances.

This system is obstacle to infectious agents (bacterial, viral, fungal). When the immune system fails, the likelihood of infections increases, this also leads to the emergence of autoimmune diseases, including multiple sclerosis.

The content of the article:

Organs of the human immune system

The organs included in the immune system: lymph glands (nodes) tonsils, thymus gland (thymus gland), bone marrow, spleen and lymphoid formation of the intestine (Peyer's patches). They have a complicated circulation system, which consists of ducts that connect the lymph nodes.

Lymph node – is the formation of the soft tissue, which is oval, 0.2 – 1.0 cm and contains a large number of lymphocytes.

The tonsils are small clusters of lymphoid tissue located on either side of the pharynx.

Spleen – an organ that looks very similar to a large lymph node. Functions of the spleen are diverse, and the filter for the blood, and storage for its cells, and the production site of lymphocytes. In the spleen of old and defective blood cells are destroyed. Is this the body's immune system in the abdomen below the left costal margin near the stomach.

Thymus gland (thymus) is located behind the breastbone. Lymphoid cells in the thymus breeding and "learn". In children and young adults, the thymus is active, than older people, the body becomes more passive and smaller.

Bone marrow is the soft spongy tissue located inside of the tubular and flat bones. The main task of the bone marrow production of blood cells: leukocytes, erythrocytes, thrombocytes.

Peyer's patches – is a concentration of lymphoid tissue in the walls of the intestine, particularly the Appendix (the Appendix).However, the main role is played by the circulation system, consisting of ducts that connect the lymph nodes and lymph transporterowych.

Lymphatic fluid (lymph) is a liquid without color, flowing through the lymphatic vessels, it contains a lot of lymphocytes – white blood cells involved in protecting the body from disease.

Lymphocytes – is, figuratively speaking, the "soldiers"of the immune system, they are responsible for the destruction of foreign organisms, or patients own cells (infected, tumor, etc.). The most important types of lymphocytes – b-lymphocytes and T-lymphocytes. They work together with other immune cells and do not invade the body of foreign substances (infectious agents, foreign proteins, etc.). In the first phase of development of the human immune system the body"teaches"T - lymphocytes to distinguish foreign proteins from normal (his) proteins of the body. This learning process takes place in the thymus (thymus) in early childhood, because at this age the thymus is most active. When the child reaches puberty, it is the thymus decreases in size and loses its activity.

Interesting fact: in many autoimmune diseases such as multiple sclerosis, the immune system"learns" the healthy tissue your body treats them as foreign cells and starts to attack them and destroy.

The role of the human immune system

The immune system emerged along with multicellular organisms, and evolved as a helper to their survival. She combines the organs and tissues which protect the body from genetically foreign cells and substances from the environment. On the organization and mechanisms of functioning of the immune system similar to the nervous system.

Both of these systems provided by the Central and peripheral organs, capable of responding to different signals, have a large number of receptor structures and specific memory.

To the Central immune organs include red bone marrow, thymus, and peripheral – lymph nodes, spleen, tonsils, Appendix.

A leading place among the cells of the immune system is white blood cells. With their help the body is able to provide different forms of the immune response upon contact with foreign bodies, for example, the formation of specific antibodies.

History of the study of immunity

The concept of "immunity"in modern science was made by Russian scientist I. I. Mechnikov and the German physician P. Erlich, who studied the protective reaction of the body to fight against various diseases, firstall, infectious. Their joint work in this area was even noted in 1908 the Nobel prize. A great contribution to the science of immunology has also made the work of the French scientist Louis Pasteur developed the technique of vaccination against a number of dangerous infections.

The word"immunity"comes from the Latin"immunis"that means"pure anything". Initially it was thought that the immune system is to protect us from infectious diseases. However, studies of the English scientist P. Medawar in the mid-twentieth century proved that the immune system provides protection at all from any foreign and harmful interference in the human body.

Currently, under the immunity understand, firstly, resistance to infections, and secondly, the response of the organism, aimed at destroying and removing all that is alien to him and threatens. It is clear that not whether people have immunity, they simply could not exist, and that his presence allows you to successfully fight the disease and live to old age.

The immune system

The immune system has formed over the years of human evolution and acts like a well-oiled machine. It helps us to fight diseases and harmful environmental effects. The task of the immune system to recognize, destroy and output as penetrating from outside foreign agents, and formed in the body of the decay products (with infectious-inflammatory processes), as well as to destroy pathologically changed cells.

The immune system is able to recognize many "outsiders". Among them viruses, bacteria, poisonous substances of plant or animal origin, protozoa, fungi, allergens. The number of enemies she will take and turned into cancer, and therefore became a threat of its own cells. The main goal of immunity is to provide protection from intrusion and to preserve the integrity of the internal environment of the organism, its biological individuality.

How is the recognition of "strangers"? This process goes on at the genetic level. The fact that every cell has its inherent only to that particular organism's genetic information (you can call it a label). Her immune system analyzes and detects when the penetration of the body or changes in it. If the information matches (label stock), then your, if not the same (label missing), then someone else.

In immunology foreign agents are called antigens. When the immune system detects them immediately included safeguards against the "outsider" fighting begins. And for the destruction of each specific antigen, the body produces specific cells called antibodies. They approachantigens like a lock and key. Antibodies bind with the antigen and eliminate it so the body and fights disease.

Allergic reactions

One of the main immune reactions is allergies – as the enhanced response of the organism to allergens. Allergens are substances that contribute to the appearance of the corresponding reaction. Allocate internal and external factors provocateurs allergies.

To external allergens include certain foods (eggs, chocolate, citrus fruits), various chemicals (perfumes, deodorants), medication.

Internal allergens own cells, usually with changed properties. For example, for burns the body recognizes the dead tissues as foreign and creates antibodies to them. The same reactions can occur when the bee stings, Bumble bees and other insects.

Allergy develops rapidly or consistently. When the allergen acts on the body first, then the immune system are produced and accumulate antibodies with increased sensitivity to it. With repeated contact with the same allergen in the body, thus causing an allergic reaction, for example, appears skin rash, swelling, redness and itching.