CIRCADIAN

• WHAT ARE THE TYPES OF BIOLOGICAL RHYTHM?

  circadian, infradian, ultradian
• DEFINITION OF A CIRCADIAN RHYTHM?

  rhythm that occurs once in 24 hours
• EXAMPLE OF A CIRCADIAN RHYTHM?

  sleep/ wake cycle
• WHAT ARE ENDOGENOUS PACEMAKERS?

  internal factors affecting rhythms
• WHAT ARE EXOGENOUS ZEITGEBERS?

  external factors affecting rhythms
• ENDOGENOUS PACEMAKERS INVOLVED IN SLEEP/WAKE CYCLE?

  • superchiasmatic nucleus
  • pineal gland
  • melatonin
• EXOGENOUS ZEITGEBERS INVOLVED IN SLEEP/WAKE CYCLE?

  • light
  • social cues
• RESEARCH STUDY FOR CIRCADIAN RHYTHM?

  Siffre's Cave Study
• WHAT WAS SIFFRE'S CAVE STUDY?

  • Siffre lived in a cave for extended periods of time
  • in both instances despite lack of natural light, his sleep schedule only shifted to once every 25 hours
  • suggests we have free running biological rhythm regulated by internal factors
• DISCUSSION OF SIFFRE'S CAVE STUDY?

  Not generalisable

  • case study
  • cannot tell if all individual's rhythms would be influenced in same way if deprived

  Reduced validity

  • light may have influenced rhythm as an external factor
  • rhythm not free-running
  • as influenced by light