[Role of free radicals in the physiological processes].

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are produced during variety of biological processes. Low concentration of these molecules influences cell growth, differentiation or proliferation. Above derivatives of oxygen and nitrogen take part in physiological processes such as signal transduction, regulation of protein kinases or transcription factors. ROS and RNS regulate redox balance, regulate immune responses, activate macrophages and neutrophils. Under theirs' control is cell adhesion and relaxation of smooth muscles. These molecules are very important for correct function and life of the cell.