The physiological mechanisms that govern the rhythmic occurrence of certain biochemical, physiological, and behavioral phenomena.

Synonyms: Oscillator, Biologic, Biological Oscillator, Biologic Oscillator, Biologic Clocks, Biologic Oscillators, Clock, Biologic, Pacemakers, Biologic, Endogenous Oscillators, Oscillators, Biologic, Oscillator, Biological, Clock, Biological, Oscillators, Endogenous, Biological Pacemakers, Biological Oscillators, Biological Clocks, Biological Pacemaker, Biologic Pacemakers, Clocks, Biologic, Pacemaker, Biological, Endogenous Oscillator, Pacemakers, Biological, Biological Clock, Clocks, Biological, Biologic Clock, Oscillator, Endogenous, Pacemaker, Biologic, Biologic Pacemaker, Oscillators, Biological