IMMUNE SYSTEM IN PHYSIOLOGY

Abstract: The immune system is a network of biological processes that protect the body from diseases. It recognizes various pathogens, from viruses to parasitic worms and dust mites, as well as cancer cells and even wood shavings, mounts an immunological response to them, and distinguishes them from healthy tissues of the body. In most biological species, the immune system consists of two main subgroups. The innate immune system provides protection through pre-formed immune responses to various situations and influences. The adaptive immune system easily recognizes previously encountered molecules and responds to each new stimulus in a customized manner. Both systems use molecules and cells to perform their functions. Almost all organisms have some form of immunity. Bacteria have rudimentary immunity in the form of enzymes that protect against viral infections. Other simple immune mechanisms evolved in ancient plants and animals and have been passed down to their modern descendants. These mechanisms include phagocytosis, antimicrobial peptides called defensins, and the complement system KEYWORDS: Immune system, innate immunity, adaptive immunity, humoral immunity, cellular immunity, antigen, antibody (immunoglobulins: IgA, IgG, IgM, IgE, IgD), phagocytosis, T-lymphocytes, B-lymphocytes, Natural killer cells (NK cells), immune memory, allergic reactions, anaphylactic shock, histamine, autoimmune diseases