The word immunity comes from the Latin word immunitas. Immunity is defined as the body's resistance against various diseases. Its proper functioning ensures an organisms protection against morbid microorganisms, viruses, bacteria, fungi, parasites but also allergens and carcinogenic and atrophied cells. The immune system has a very complex mechanism, its task is to maintain the balance of the internal body and ensure protection against the aforementioned harmful substances and influences.
The immune system is composed of a complex collection of cells and organs that collaborate in protecting the body against foreign invaders. The immune organs are found throughout the body and together with the nervous, cardiac, motor and digestive systems ensure the harmonious action of the body as a whole. The basis of the function of the immune system is a complicated and dynamic communication network. When the immune cells meet with the foreign invader they begin to produce various chemicals. These substances facilitate cells to regulate their growth and mobilize other cells while simultaneously directing them to problematic and vulnerable places. When the immunity fails or is weakened, we are more exposed to various diseases. People with a weakened immunity often experience frequent colds, repeated infections, but also flu, allergy, arthritis, and in some cases cancer.
Our immunity is made up of two lines of protection, which we recognize under the name of natural and acquired immunity.
Natural immunity is composed of the body's first line of protection. It is genetically defined, congenital and non-specific. From the moment of birth congenital immunity facilitates man to protect himself from harmful substances from the outside and from various morbid bodies. Natural immunity also comprises some blood cells, which are capable of intervening at the site of invasion of a foreign microorganism. Additional important protective barriers are the skin and mucus that lines our airways.
The acquired immunity is specific and represents the second line of protection of the organism. It is shaped during life through contact with foreign substances (e.g. bacteria) which have not been eliminated by the first line of protection. The functioning of the acquired immunity is ensured by a complex of cells and proteins, which we know under the denomination antibodies. The acquired immunity and its formation are not activated immediately after the encounter of a certain antigen with the immune system but only after a while. Exactly because of this reason the first phase is important for the separation and differentiation of cells and the creation of antibodies.