How Body Functions and Internal Clock Proteins Interact

Endogenous circadian rhythms in mammals persist even without environmental timing cues.

• Circadian rhythms are generated by intracellular timing mechanisms known as circadian clocks.
• The master clock is located in the suprachiasmatic nuclei (SCN), with additional clocks in other brain regions and peripheral tissues.
• Circadian clocks respond to environmental cues, particularly light/dark and feeding/fasting cycles.
• Physiological cues, such as the energetic status of cells, can influence the functioning of circadian clocks.
• Post-translational modifications of clock proteins are essential for regulating the timing and feedback mechanisms of circadian rhythms.

Simplified