Circadian Rhythms Flashcards
What are endogenous pacemakers?
Internal body clocks
What are exogenous zeitgebers
External cues
What are ultradian rhythms?
Cycles During the day
What are infradian rhythms?
Last longer than a day
What are circadian rhythms?
Last around 24hrs
What is an exogenous zeitgeber that controls the sleep wake cycle?
Daylight
What is the sleep wake cycle governed by?
Super charismatic nucleus (SCN) which is an endogenous pacemaker (light info received by eyes)
Describe Siffre’s cave study
Deprived of natural light and sound.
Access to adequate food and drink.
Spent 2 months in a cave but believed he spent mid September to august in the cave.
Repeated it in a Texan cave and his free running biological rhythm settled to 25hrs not 24hrs.
Describe Aschoff and Weaver’s research
WW2 bunker for 4 weeks.
Deprived of natural light.
S/W cycle extended to 24-25hrs.
Suggests S/W cycle longer than 24hrs
Describe Folkard et al research
Study of 12 people who lived in a cave for 3 weeks.
Bed when clock said 11:45pm and wake when clock said 7:45am
Researchers sped the clock up over the study. (24hrs-22hrs over time)
One person was able to comfortably adjust to new regime. Suggests existence of a strong free running circadian rhythm that cannot be easily overridden by exogenous zeitgebers.,
One strength of circadian rhythms research is shift workers (AO3)
Provides understanding of adverse consequences that occur when they are disrupted. Eg. Night workers engage in shift worm experience reduced concentration around 6 in the morning, mistakes and accidents likely.
Relationship between shift work and poor health (3x more likely to get heart disease)
Counterpoint of shift work (AO3)
Studies investigating this use correlation methods so hard to establish is disrupted S/W cycle is actually a cause of negative effects (other factors)
Eg. High divorce rate in shift workers may be due to strain of deprived sleep, suggests not always biological.
One strength of circadian rhythms research is medical treatment (AO3)
Circadian rhythms coordinate a number of processes such as heart rate digestion and hormones levels. Rise and fall in the day has led to field of chronothraputics. Medical treatment administered in a way that corresponds to someone’s biological rhythms (increase drug effectiveness)
