The photoperiod as the basic temporary integrator of functional systems of all alive organisms, including man, was considered in this review. The concept about chronoperiodic and photoperiodic systems as the functional systems of the human organism was offered. Chronoperiodic and photoperiodic systems allow to synchronize the chronorhythms of different somatic and visceral functions and also realize the coordination and the modulation of mechanisms adaptation to the stressors influence.
