Figure 4.

The association of the input signals, circadian homeostasis, and diseases. Intertwining interactions between the circadian clock and diseases are complex, and essentially depend not only on physiological factors alone, but also the influence of the different zeitgebers like, lights, sounds, temperature, feeding behaviors, lifestyles, and social timing received by the individual. Every individual clock needs to be synchronized within the tissue to sustain the stable phase-relationship to render the clock-mediated rhythmic information. The cellular clocks perceive the input signals by responding to the stimuli (input signals), integrate the phases to sense the temporal information and transmit the rhythmic information to other cells (circadian outputs) to adjust the indigenous clock timing with the external cues. This homeostatic mechanism drives the temporal regulations of different physiological functions. Disruption of such homeostasis leads to abnormal physiological activities and develops different diseases.