Circadian rhythms

• Circadian rhythms - a pattern of behaviour that occurs every 24 hours , & which are set & reset by environmental light levels
• Circadian rhythms evaluation:

  • Research support for the importance of light - after 3 months of darkness in antarctica, normal cortisol patterns had changed
  • Individual differences - can vary from 13 to 65 hours, difference in cycle peaks - explains why people have different sleep times
  • Research methodology - early research ignored importance of artificial light
  • Real world application Chronotherapeutics - lead to development on how timing affects drugs
  • Importance of temperature - body temperature is a circadian rhythm & small changes can set the timing of cells
• Circadian rhythms:

  • A pattern of behaviour that occurs every 24 hours & which is reset by environmnetal light levels
  • The master circadian pacemaker is the suprachiasmatic nuclei in the hypothalamus
  • The SCN is rest daiy by light. Light-sensitive cells within the eye act as brightness detectors
  • The sleep-wake cycle is under circadian & homeostatic control
  • Core body temperature varies with a circadian rhythm
  • Hormone release follows a circadian rhythm
• Circadian rhythms AO3:

  • Research support for the importance of light
  • Individual differences
  • Research methodology
  • Real world applications (Chronotherapeutics)
  • Importance of temperature