Immunity

This is the body’s ability to protect itself from harmful biological stimuli. The main task of the body’s defense mechanism is to maintain the internal homeostasis of the body, to defend against everything that is genetically foreign to it. This task is performed by the immune system. The innate or nonspecific immunity consists of physical and chemical barriers, tissue and blood phagocytic cells – phagocytes, some lymphocytes, various molecules circulating in the blood. The epidermis of the skin, digestive tract, respiratory and urinary and genital tracts form a barrier between the body’s internal environment and the external environment containing many pathogens. The acidic pH of the stomach and the digestive enzymes of the stomach and upper intestine create a chemical barrier to microorganisms. Other defense mechanisms begin to act only when the body interacts with foreign substances, and are specific to those macromolecules. This is acquired (specific) immunity.

Source | Glossary of Most Commonly Used Biomedical Terms and Concepts | Lithuanian University of Health Sciences | Academician Professor Antanas Praškevičius, Professor Laima Ivanovienė