biological rhythms

• What are the biological cycles in the body described as?

  They happen predictably over various timeframes
• What is the role of endogenous pacemakers?

  They act as an internal body clock
• What does the term 'exogenous zeitgebers' refer to?

  External cues that influence biological rhythms
• What is the process called that aligns the internal clock with external cues?

  Entrainment
• What is a circadian rhythm?

  A biological rhythm lasting around 24 hours
• How do exogenous zeitgebers affect the sleep/wake cycle?

  They provide cues that influence sleep timing
• What is the SCN and its role?

  It is the master clock regulating the sleep/wake cycle
• Where is the SCN located?

  In the hypothalamus within the limbic system
• What hormone does the pineal gland produce?

  Melatonin
• How does light affect melatonin production?

  Light suppresses melatonin production
• What is a free-running circadian rhythm?

  A rhythm maintained without external cues
• Who conducted studies on free-running circadian rhythms in caves?

  Seif
• What was the duration of Seif's cave study?

  179 days
• What did Seif's study reveal about the circadian rhythm?

  It extended to around 25 hours without cues
• What criticism was raised about Seif's study methodology?

  Participants controlled artificial light usage
• What did recent research by Caesar suggest?

  No drift in the endogenous pacemaker's rhythm
• What evidence supports the SCN as the endogenous pacemaker?

  Ralph's study with hamsters showed this
• What happened when Ralph replaced the SCN of mutant hamsters?

  They adopted a normal 24-hour rhythm
• What are the implications of understanding circadian rhythms?

  It helps develop treatments for jetlag and productivity
• What is chronobiology?

  The study of biological rhythms
• How can circadian rhythms be affected by environmental conditions?

  They can be turned off if not needed
• What is a unique adaptation of arctic reindeer regarding circadian rhythms?

  They lose their rhythm in constant daylight
• What effect does blue light exposure have on circadian rhythms?

  It can disrupt normal sleep patterns
• What was the circadian rhythm of a blind man studied by Miles?

  24.9 hours
• Why do humans have a day/night cycle adaptation?

  We are specialized for daytime activity
• How do nocturnal animals differ in their circadian rhythms?

  They shift their rhythms to be active at night
• What is a fact about cyanobacteria related to circadian rhythms?

  They also have a circadian rhythm
• How can understanding circadian rhythms benefit health services?

  It helps in timing drug treatments effectively
• What advice can be given regarding exposure to blue light?

  Limit exposure at night for better sleep
• What is the significance of social cues in circadian rhythms?

  They can help reset the biological clock
• What is the primary function of the SCN?

  To regulate the sleep/wake cycle
• What happens to circadian rhythms in constant daylight conditions?

  They can become disrupted or lost
• How do migrating birds manage their circadian rhythms?

  They can turn off their rhythms temporarily