Biopsych

• What are the two main factors that govern biological rhythms?

  Endogenous pacemakers and exogenous zeitgebers
• How does daylight influence our sleep/wake cycle?

  Daylight acts as an important exogenous zeitgeber affecting alertness and drowsiness
• What is the suprachiasmatic nucleus (SCN)?

  It is part of the hypothalamus and acts as an internal clock
• What role does the SCN play in regulating melatonin secretion?

  It regulates melatonin secretion by the pineal gland in response to light/dark cycles
• What is the most influential exogenous zeitgeber?

  Light, specifically sunlight
• What did Michael Siffre's cave study demonstrate about biological rhythms?

  It showed that biological rhythms can extend beyond the usual 24-hour cycle
• How long did Siffre believe he had been underground after two months?

  He believed it was mid-August
• What is a circadian trough?

  A period of reduced concentration typically occurring around 6 in the morning
• What are the potential health consequences of shift work?

  Shift workers are three times more likely to develop heart disease
• How long does it typically take to adjust to a new time zone when traveling?

  About a week
• What is chronotherapeutics?

  It is the study of how circadian rhythms affect drug effectiveness
• What is pharmacokinetics?

  The action of drugs on the body and how well they are absorbed and distributed
• What practical applications have arisen from research into circadian rhythms?

  Guidelines for the timing of drug dosing for various medications
• What is a limitation of studies involving small samples in sleep/wake cycle research?

  They may not be representative of the wider population
• How do social cues influence infants' sleep/wake cycles?

  Schedules imposed by parents help entrain infants' circadian rhythms
• At what age do infants typically begin to develop circadian rhythms?

  About 6 weeks of age
• What is the relationship between local times for eating and sleeping and jet lag?

  Adapting to local times can help entrain circadian rhythms and reduce jet lag
• What individual differences exist in circadian rhythms according to Duffy et al. (2001)?

  Some people are 'morning people' while others are 'evening people'
• How does temperature influence circadian rhythms according to Buhr et al. (2010)?

  Fluctuations in temperature set the timing of cells in the body
• What is the typical duration of the female menstrual cycle?

  Approximately 28 days
• What hormone is primarily involved in regulating the menstrual cycle?

  Oestrogen
• What did Stern and McClintock's study suggest about menstrual cycles?

  Menstrual cycles may synchronize due to the influence of female pheromones
• What percentage of women experienced changes to their cycle in McClintock's study?

  68%
• What is the evolutionary basis of menstrual synchrony?

  It may have been advantageous for females to menstruate together for collective care of offspring
• What criticism did Schank (2004) make regarding menstrual synchrony?

  Too many females cycling together could lead to competition for mates
• What are some confounding variables that may affect menstrual cycles?

  Stress, changes in diet, and exercise
• What is Seasonal Affective Disorder (SAD)?

  A depressive disorder with a seasonal pattern of onset
• How is SAD related to circadian rhythms?

  SAD may be due to disruption of the sleep/wake cycle from prolonged darkness
• What is one effective treatment for SAD?

  Phototherapy using a light box
• What did Eastman et al. (1998) find about phototherapy for SAD?

  It relieves symptoms in up to 60% of sufferers
• What is the typical duration of a sleep cycle?

  90-120 minutes
• How many sleep cycles does a person typically experience in a night?

  Four to five cycles
• What happens to REM sleep as the night progresses?

  REM periods lengthen while deep sleep time decreases
• What are the four stages of sleep?

  Non-REM (NREM) sleep stages 1, 2, 3, and REM sleep
• What is the role of sleep spindles and K complexes in Stage 2 sleep?

  They protect the brain from awakening from sleep
• What occurs during Stage 3 sleep?

  It is the deepest stage of sleep and the most restorative
• What hormone is released during deep sleep?

  Human growth hormone
• What is the significance of deep sleep?

  It restores the body and immune system
• What happens during REM sleep?

  Breathing becomes rapid, and vivid dreams occur
• What is muscle atonia during REM sleep?

  Temporary paralysis of limb muscles to prevent acting out dreams