circadian rhythms

• What are circadian rhythms?

  • Biological rhythms occurring approximately every 24 hours
  • Influenced by internal body clocks and external cues
  • Regulated by light levels
• What are the types of circadian rhythms?

  Sleep-wake cycle, core body temperature, hormone production
• What role do light and darkness play in circadian rhythms?

  They act as exogenous zeitgebers
• What is the function of the SCN in circadian rhythms?

  It acts as an endogenous pacemaker
• How does light affect the SCN?

  It sets the body clock through photoentrainment
• What did Siffre's cave study suggest about circadian rhythms?


  External factors like light regulate circadian rhythms
• What did Simon Folkard's research illustrate about internal body clocks?

  They are powerful and hard to override
• What are the practical applications of understanding circadian rhythms?

  • Shift times of the school day for better performance
  • Manage worker productivity in shift work
  • Improve timing of medical treatments
• How has research on circadian rhythms influenced education?

  It suggests starting school later for teens
• What are the potential negative effects of shifting school start times?

  Disruption for parents and extracurricular activities
• What adverse effects can shift work have on workers?

  Reduced concentration and increased health risks
• Why is the correlation between shift work and negative effects a limitation?

  It makes causation difficult to establish
• How has research on circadian rhythms improved medical treatments?

  By timing treatments to align with biological rhythms
• What are endogenous pacemakers and exogenous zeitgebers?

  • Endogenous pacemakers: Internal body clocks regulating rhythms
  • Exogenous zeitgebers: External cues affecting biological rhythms
• What is the role of the SCN in the body?


  It generates the body's circadian rhythm
• How does the SCN communicate with the body?


  By sending signals in response to light
• Why does the timing of taking aspirin matter?

  It affects the effectiveness of drug treatments
• How can research on circadian rhythms benefit drug treatments?

  It can increase their effectiveness
• What are endogenous pacemakers?

  Internal biological clocks regulating rhythms
• What are exogenous zeitgebers?

  External cues that reset biological clocks
• What role does the SCN play in biological rhythms?

  It generates the body's circadian rhythm
• Where is the SCN located?

  In the hypothalamus of the brain
• How does the SCN respond to light and dark?

  It sends signals throughout the body
• Why does the SCN need resetting?

  When external light levels change
• How does the SCN receive information about light levels?

  Via the optic nerve
• What happens to the SCN's function when the eyes are closed?

  It still receives light information
• What does the SCN regulate in the pineal gland?

  Melatonin production and secretion
• How does melatonin affect sleep?

  It induces sleep by inhibiting wakefulness
• What is the role of exogenous zeitgebers in biological rhythms?

  They reset biological clocks through entrainment
• What is the free running biological clock?

  A clock that continues in a cyclical pattern
• How does light function as an exogenous zeitgeber?

  It resets the SCN and maintains sleep-wake cycles
• How do social cues influence circadian rhythms in infants?

  They help entrain sleep/wake cycles
• What did DeCoursey et al (2000) study demonstrate?


  SCN is crucial for the sleep-wake cycle
• Why can findings from animal studies be generalized to humans?

  Similar mechanisms exist in both species
• What ethical concern arises from DeCoursey et al's study?


  Animals were exposed to harm and risk
• What is a limitation of SCN research?

  It may overlook other body clocks
• What are peripheral oscillators?

  Other circadian rhythms in organs and cells
• How can feeding patterns affect circadian rhythms?

  They can alter liver cell rhythms significantly
• What did Campbell and Murphy (1998) demonstrate about light?


  Light can be detected by skin receptors
• What limitation exists regarding exogenous zeitgebers?

  They do not affect all environments equally