Immunity - is a set of defense mechanisms that help the body in fighting with the heterogeneous factors: bacteria, viruses, toxins, heterogeneous bo

Humoral immunity and immune system

Immunity — is a set of defense mechanisms that help the body in fighting with the heterogeneous factors: bacteria, viruses, toxins, heterogeneous bodies, and others.

Cellular immunity, or phagocytosis, plays a very important role in the local inflammatory processes. Humoral immunity becomes more important when the whole body is infected. Its main manifestation is the formation of certain types of white blood cells — lymphocytes — the antibodies, which suppress the harmful effects of various infectious (bacteria, viruses, microscopic fungi, etc.) and non-infectious (plant pollen, medicines, foreign proteins, and others) factors.

Different structures of the body, united in the immune system are attended in the formation, maturation and “studying” of lymphocytes in production of antibodies (immune response). The spot of lymphocytes formation are lymph nodes and spleen, as well as accumulation of lymphoid tissues in the digestive system (e.g. in appendix) and airway. However, at the stage of formation lymphocytes are still unable to recognize foreign substances of protein or polysaccharide nature, which are called antigens. Lymphocytes mature and “learn” to recognize foreign bodies in the thymus. Immune system is subordinated by a higher regulatory neurohumoral centers: cerebral cortex, hypothalamus, pituitary, adrenal, etc. Chronic stress, negative emotions, depressed mood significantly reduce immunity. Formation of an immune response is also directly depends on metabolism; any violation of the metabolism also leads to immune disorders. Consequently, the immune response is the result of the entire human body activities.

Diagram 56. Specificity of antibodies 1 — antibody molecule; 2 — different types of bacteria; 3 — poor affinity (specificity); 4 — a stronger affinity (specificity); 5 — strong binding of antibodies to the bacteria and bacterial clearance (high specificity)

The main active factor of humoral immunity is antibodies. They have a relationship with heterogeneous factors on a “lock and key” principle. The closer this relationship and specificity, the more effective the “fight” of antibodies with the harmful factor (diagram 56). Taken from http://worldofschool.org

Antibodies — are blood proteins that destroy not only bacteria and viruses but also neutralize their toxins or other chemicals.

Factors that impair the immune status of an organism are malnutrition (especially lack of protein, vitamins), chemicals (industrial and domestic), frequent hypothermia and overheating. Excess exposure of the sun significantly violates the immune status of the body. However, the most damages immune system gets of the radioactive radiation, because it destroys the white blood cells and vital organs such as the red bone marrow, spleen, lymph nodes, thymus and skin.

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Questions:
  • Explain the origin of the “immunity” concept.

  • Explain the mechanism of humoral immunity.

  • What is the specificity of antibodies?

  • What structures of the body are involved in the immune response?

  • How and what the immune system is subordinated to?

  • What is negative effect of radiation and chemical pollution on the human immune system?