Immunological system

Immunity is a set of all defense mechanisms which take part in creation of immunological response. In other words, immunity is an ability to actively and passively protect the organism against pathogens. All immunity mechanisms gathered together create the immune system.

Human immune system consists of the thymus, spleen, lymph nodes, bone marrow, tonsils and parts of intestine. Its key function is production and storage of white blood cells, which assure immunological response. Immunological response consists in antigen recognition and attack by scavenger cells (macrophages and neutrophils) and afterwards in destruction by lymphocytes T and B. Immunology is part of medicine which takes care of interaction mechanisms between the human body and microorganisms and pathogens.

We can distinguish the following types of immunity:

• non-specific immunity, passive (resistance):
  • low pH on the skin surface (pH 3-5), in the vagina (lactic acid) and in the stomach (hydrochloric acid)
  • occurrence of bactericidal secretion ingredients, such as lysozyme in tears or interferon in blood, lactoferrin in milk during lactation, saliva, tears, colostrum, natural bacterial microflora in the intestine.
     

• non-specific immunity, active:
  • sudden cleaning reaction of air-passages and the gastrointestinal tract, among others: cough, sneezing, vomiting, diarrhea,
  • increased body temperature and accelerated metabolism,
  • phagocytosis.
     

• specific immunity, active:
  • production of lymphocytes B, which in contact with the antigen are activated and transformed into plasmocytes,
  • antibodies, in other words immunoglobulins, which have the ability for specific interaction with antigens,
  • lymphocytes T, which mature in the thymus, where they obtain the ability for immunological response.
     

• specific immunity, passive:
  • consists in possessing lymphocytes B and T and antibodies, which come from outside of the body
  • specific, passive, natural immunity: the source of defense factors is the mother’s blood (delivered through the placenta)
  • specific, passive, artificial: the source for defense factors is administered serum.