Physiology of Circadian Rhythm
Karuna Datta
Abstract
This chapter lays out the basic concept of circadian rhythm, including the molecular clock concept and interrelationship of the master clock to the peripheral clocks. Genetic aberrations and metabolic derangements that cause circadian disruptions can be understood by understanding the rhythm generation at the molecular clock level. Further, the concept of the two-process model, i.e., Process C and Process S, is explained. The role of various photic and nonphotic inputs that can entrain the circadian rhythm is discussed, which helps in understanding these modalities as therapeutic agents in the management of circadian rhythm disorders. The chapter discusses the interrelationship of the processing of these photic and nonphotic inputs just to make the reader understand the importance of circadian physiology for normal body functioning.