Biological rhythms

• What are biological rhythms?

  Cyclical changes in biological functions
• What types of rhythms are classified under biological rhythms?

  Ultradian, Circadian, and Infradian rhythms
• What is an example of an ultradian rhythm?

  Stages within sleep
• What is an example of a circadian rhythm?

  Sleep-wake cycle

  
• What is an example of an infradian rhythm?

  Menstrual cycle
• What are endogenous pacemakers?

  Internal mechanisms controlling biological rhythms

  
• What are exogenous Zeitgebers?

  External factors that influence biological rhythms

  
• What are the three types of biological rhythms and their cycles?

  • Ultradian: Cycles < 24h (e.g., stages of sleep)
  • Circadian: Cycles = 24h (e.g., sleep-wake cycle)
  • Infradian: Cycles > 24h (e.g., menstruation)

  
• What is the role of the Suprachiasmatic Nucleus (SCN)?

  It acts as the body's biological clock

  
• How does the SCN respond to light?

  It detects light and regulates melatonin production

  
• What hormone does the SCN stimulate the pineal gland to produce?

  Melatonin

  
• What is the main exogenous Zeitgeber?

  Light
• What did Siffre's study involve?

  Living in a cave without natural light
• What was the duration of Siffre's first study?

  6 months
• What did Siffre use to record his experiences?

  A diary
• What did Siffre find about his circadian rhythm?

  It lasted a little longer than 24 hours
• What did Folkard's study demonstrate?

  Most subjects maintained a 24-hour cycle
• What was the sleep-wake cycle duration in Aschoff & Wever's study?

  29 hours
• What happened to the chipmunks in DeCoursey et al.'s study?

  Their sleep-wake cycle disappeared
• What are the weaknesses of the research on biological rhythms?

  • Siffre's study is based on one person
  • Aschoff and Wever had a small sample
  • Animal studies have limited generalizability
  • Individual differences in sleep-wake preferences
• What health problems do shift workers face?

  Mental and physical health problems
• What is a real-world application of biological rhythms research?

  Improved shift patterns for workers
• How does international air travel affect biological rhythms?

  It disrupts biological rhythms significantly
• What treatments can lessen the effects of jet lag?

  Light therapy and melatonin supplementation
• What are the practical applications of biological rhythms research?

  • Shift work patterns to reduce health risks
  • Drug treatments based on pharmacokinetics
  • Addressing jet lag with light therapy
• What is the relationship between shift work and heart disease?

  Shift workers are more likely to develop heart disease
• Who conducted the study on the effects of shift work on health?

  Knutsson
• What are biological rhythms?

  Cyclic variations in body functions
• What are the three types of biological rhythms?

  • Ultradian
  • Circadian
  • Infradian

  
• What does 'ultradian' refer to in biological rhythms?

  Cycles shorter than 24 hours

  
• What does 'circadian' refer to in biological rhythms?

  Cycles that last about 24 hours
• What does 'infradian' refer to in biological rhythms?

  Cycles longer than 24 hours

  
• Give an example of an ultradian rhythm.

  Stages of sleep

  
• Give an example of a circadian rhythm.

  Sleep-wake cycle

  
• Give an example of an infradian rhythm.

  Menstrual cycle

  
• What are the two notable infradian cycles in humans?

  • Menstrual Cycle
  • Seasonal Affective Disorder (SAD)
• How is the menstrual cycle controlled?

  By hormones from the ovary and pituitary gland
• What hormones control the menstrual cycle?

  Oestrogen, progesterone, LH, FSH

  
• What is the duration of the menstrual cycle?

  23-36 days
• What role does oestrogen play in the menstrual cycle?

  It develops an egg and triggers ovulation