Circadian rhythms

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

  • A pattern of behaviour that occurs every 24 hours & which is reset by environmental 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 - Siffre cave study ; his circadian rhythm settled to 25 hours - suggets sleep-wake cycle is controlled internally but external cues are important
  • ✅ Real world applications - chronotherapeutics, how timing affects drugs ( e.g. heart attacks are more likely in the morning so drugs are more effective when taken at night )
  • ❌ Individual differences - differences in peak times. Also affected by age
  • ❌ Research methodology - early research ignored importance of artificial light - reduces internal validity
• Circadian rhythms AO3:

  • ✅ Research support
  • ✅ Real world applications
  • ❌ Individual differences
  • ❌ Research methodology