circadian rhythms

• What is a biological rhythm?

  Distinct patterns of changes in body functions
• What is a circadian rhythm?

  Biological rhythms with a period of about 24 hours
• What are endogenous pacemakers?

  Biological clocks regulating rhythms independently
• What are zeitgebers?

  Environmental changes that synchronize biological rhythms
• What physiological changes are associated with circadian rhythms?

  Sleep-wake cycle and core body temperature
• How much does core body temperature vary during the day?

  Around three degrees Celsius
• When is core body temperature lowest?

  Around 4 am
• When is core body temperature highest?

  Around 4 pm
• What impact does core body temperature have on performance?

  It affects performance and alertness
• What did the study comparing school start times find?

  Children starting at 9 am performed better
• What are the key features of circadian rhythms?

  • Regulate sleep/wake cycles
  • Influence body temperature fluctuations
  • Affected by external zeitgebers
• What is the role of the suprachiasmatic nucleus (SCN)?

  Regulates biological clock and melatonin production
• What happens to circadian rhythms in the absence of external cues?

  The rhythm persists but may extend to 25 hours
• What did Michel Siffre's cave study investigate?

  The effects of absence of light on circadian rhythms
• What was a key finding from Siffre's study?

  His rhythms were around 25 hours
• What did Sargent and Water's study find about participants in a bunker?

  Participants exhibited longer than 24-hour rhythms
• What is a limitation of the studies on circadian rhythms mentioned?

  Small number of participants and short duration
• What is a potential cause of illness in night shift workers?

  Disrupted sleep and high-stress levels
• What is a strength of research into circadian rhythms?

  Understanding adverse consequences of disruptions
• Why is it difficult to establish cause and effect in shift work studies?

  Studies are often correlational and confounded
• How has medical treatment research improved health?

  By timing drug administration effectively
• What is a limitation of research into circadian rhythms regarding individual differences?

  Generational differences are difficult to study
• What did Charles Czeisler's study find about human circadian rhythms?

  They vary among individuals significantly
• What are the benefits of shifting the school day later?

  • Improved student attendance
  • Enhanced concentration and performance
  • Reduced reliance on caffeine
  • Fewer car accidents
• What is Jed's work pattern?

  Changing shifts with night and day work
• How has Jed's biological rhythm been affected?

  Difficulty adapting to shift changes
• What strategies could help Jed cope with his irregular hours?

  Implementing precautions to improve rest
• What is a meta-analysis?

  A study that combines results from multiple studies
• What criteria should be met before conducting a meta-analysis?

  Relevance, quality, and sample size of studies
• What is one strength of conducting a meta-analysis?

  Provides a comprehensive overview of research
• What is one limitation of conducting a meta-analysis?

  Quality of included studies may vary
• What accounts for variability in sleep/wake cycles?

  Individual differences and environmental factors
• How might age affect sleep/wake cycles?

  Age can influence duration and patterning
• What are zeitgebers?

  Environmental cues that influence biological rhythms
• Describe three methods of research into circadian rhythms.

  Case studies, experiments, and observational studies
• Discuss research into circadian rhythms.

  Research shows effects of disruptions and individual variability