sleep wake cycle - circadian rhythm

• What are the biological cycles in the human body described in the study material?

  They occur predictably, some many times a day, some once every 24 hours, and some take weeks or years.
• What is the role of endogenous pacemakers in the body?

  They act as an internal body clock that helps keep track of biological cycles.
• What does the term "exogenous zeitgeber" refer to?

  It refers to external environmental cues that help regulate the internal body clock.
• What is the process called that involves the interaction between endogenous pacemakers and exogenous zeitgebers?

  This process is known as entrainment.
• What is a circadian rhythm?

  A circadian rhythm is a biological rhythm that lasts around 24 hours.
• What is the most obvious example of a circadian rhythm?

  The sleep/wake cycle is the most obvious example.
• How does light affect the sleep/wake cycle?

  Light received by the eyes suppresses melatonin production, making you feel less sleepy.
• What happens during jet lag in relation to endogenous pacemakers and exogenous zeitgebers?

  Jet lag occurs when there is a conflict between the internal body clock and external cues like light.
• What is the role of the suprachiasmatic nucleus (SCN) in the sleep/wake cycle?

  The SCN is the endogenous pacemaker responsible for regulating the sleep/wake cycle.
• How does the SCN interact with the pineal gland?

  The SCN detects light and regulates melatonin production in the pineal gland.
• What is the effect of strong blue light on circadian rhythms according to the study?

  Strong blue light can synchronize circadian rhythms with office lighting.
• What evidence supports the role of the SCN as the endogenous pacemaker?

  Research showed that transplanting the SCN from normal hamsters to mutant hamsters restored their circadian rhythm to 24 hours.
• What are the implications of understanding circadian rhythms for psychology and health services?

  Understanding circadian rhythms can help develop treatments for jet lag and improve productivity for shift workers.
• How can exposure to blue light at night affect sleep patterns?

  Exposure to blue light at night can disrupt the biological clock and lead to poor sleep quality.
• What is chronobiology?

  Chronobiology is the study of biological rhythms and their effects on living organisms.
• How do some species adapt their circadian rhythms in extreme environments?

  Some species can turn off their circadian rhythms when conditions, like constant daylight, do not require them.
• What is the significance of the study on a blind man regarding circadian rhythms?

  The study showed that even without visual cues, the blind man maintained a circadian rhythm close to 24 hours.
• What are the biological cycles in the body described in the study material?

  They occur predictably, some many times a day, some once every 24 hours, and some take weeks or years.
• What is the role of endogenous pacemakers in the body?

  They act as an internal body clock that helps keep track of biological cycles.
• What does the term "exogenous zeitgeber" refer to?

  It refers to external environmental cues that help regulate the internal body clock.
• What is the process of entrainment?

  It is the process by which external cues synchronize the internal body clock.
• What is a circadian rhythm?

  A biological rhythm that lasts around 24 hours.
• What is the most obvious example of a circadian rhythm?

  The sleep/wake cycle.
• How do exogenous zeitgebers affect the sleep/wake cycle?

  They can conflict with the internal body clock, as seen in jetlag.
• What is the role of the suprachiasmatic nucleus (SCN)?

  It is the endogenous pacemaker for the sleep/wake cycle.
• Where is the SCN located?

  In the hypothalamus within the limbic system.
• How does the SCN influence melatonin production?

  It suppresses melatonin production in response to light detected by the eyes.
• What is the effect of light on the SCN?

  Light received by the eyes influences the SCN's regulation of the sleep/wake cycle.
• What did Seif's studies on free-running circadian rhythms demonstrate?

  They showed that the endogenous biological rhythm can maintain itself without external cues.
• What was the duration of Seif's cave study?

  179 days.
• What was the result of Seif's isolation from natural light?

  His body clock extended to around 25 hours while maintaining a regular sleep/wake pattern.
• What criticism was raised regarding Seif's study methodology?

  Participants had control over artificial lights, which could alter their biological clock.
• What did Ralph's experiment with hamsters demonstrate about the SCN?

  It showed that the SCN is the endogenous pacemaker responsible for the sleep/wake cycle.
• What was the circadian rhythm of the mutant hamsters in Ralph's study?

  20 hours.
• What happens when normal hamsters receive the SCN from mutant hamsters?

  They adopt a 20-hour sleep/wake cycle.
• How can understanding circadian rhythms benefit health services?

  It can help in timing drug treatments and improving health outcomes.
• What are the implications of increased exposure to blue light at night?

  It can disrupt sleep patterns and affect health.
• What did the study on a blind man reveal about circadian rhythms?

  He had a circadian rhythm of 24.9 hours despite social cues.
• What is chronobiology?

  It is the study of biological rhythms.
• How do some species adapt their circadian rhythms in extreme environments?

  They can turn off their circadian rhythms when not needed, such as during continuous daylight.