THE ROLE OF THE CIRCADIAN SYSTEM IN MAINTAINING HOMEOSTASIS OF THE MAMMALIAN ORGANISM (LITERATURE REVIEW)
One of the most significant factors that affect life on our planet is the cyclic change of day and night. For successful adaptation to and survival in the environment, various creatures from unicellular to mammals have developed mechanisms of synchronization with external conditions to control body functions in accordance with daily light changes and ambient temperature. This has led to the emergence of rhythms that regulate physiological processes, which were called circadian rhythms. In animals, these rhythms primarily affect the work of the nervous and endocrine systems which regulate their behaviour and internal environment. The operation of the circadian clock in the suprachiasmatic nucleus of the hypothalamus is the basis of circadian regulation. The suprachiasmatic nucleus has connections with many of the central nervous system structures, which provides clear and stable rhythms of regulatory processes in the body. Peripheral tissues also have a cellular circadian clock that is synchronized with the central clock in the suprachiasmatic nucleus. The circadian system provides adequate body regulation without synchronization with external conditions, but it is vulnerable to various factors.