The immune system includes central organs (thymus and bone marrow), peripheral systems and organs (lymph nodes and lymphoid accumulations in various organs, spleen); pathways of immunocompetent cells circulation. It also contains humoral factors, soluble molecules that are the product of B-lymphocytes (antibodies, immunoglobulins), and cytokines – soluble mediators of intercellular interactions.
The main cells of the immune system are leukocytes, including macrophages, neutrophils, and lymphocytes. Soluble substances are molecules that are not contained in cells, but in a liquid, for example, in blood plasma. These include antibodies, complement proteins, and cytokines. Some soluble substances act as mediators, attracting and activating other cells. Molecules of the main histocompatibility complex make it possible to distinguish “normal” from “alien,” like a firewall in an operating system on a computer.
In providing the body’s immune function, the lymphatic system closely interacts with the circulatory system, skin, and mucous membranes, as well as with other organs. According to the anatomical and physiological principle, the immune system is organo-circulatory, that is, lymphocytes constantly circulate between non-lymphoid tissues and lymphoid organs through lymphatic vessels and blood, like a corporate document circulation system.
Basophils act like a fire alarm on premises, detecting and alerting about the occurrence of a fire. Until recently, the main function of basophils was considered to be the attraction of leukocytes and mediators to the focus of infection. However, scientific research in recent years has significantly expanded the understanding of their role in the body. Basophils are now perceived as the main effector cells of allergy, i.e., cells, the activity of which leads to the symptoms of the disease.
In all its parameters, functional capabilities, and significance for the body, the immune system has every reason to be distinguished as one of the functional systems, which is given the name of the functional system of immune homeostasis. This is not just the integration of nervous, endocrine, immune mechanisms in the reflex reactions, but the unification of all these processes by separate functional systems to achieve the adaptive results required for the body.