Exogenous Zeitgebers^ Flashcards
Exogenous Zeitgebers
external factors in envi that reset bio clocks through entrainment
Social Cues
infants don’t exhibit a rhythmic cycle (random)
entrainment begins at around 6 weeks
- influence on meal times/bedtimes
- solified by about 6 weeks
Jet Lag
- adapt to local eating and sleep times
Light
can reset the SCN by envi so can affect cycle
indirect influence on processes
- hormone secretion/ blood circulation
Campbell & Murphy
- light detected by receptors on skin
- 15 par. woken at several points by a light pad shone at the back of their knees
- caused a deviation of up to 3 hours in some cycles
Show importance of lighht as EZ, dont rely on eyes to be influential
Environmental Observations
EZ dont have the same effect in all environments
- those who live in places with extreme light/ dark
Artic Circle have similar patterns all year despite 6 months being in complete darkness
EP have more control over bio rhythms and can overrside envi changes
Case Study Evidence
Miles et al
- recount the story of a young blind mean with circadian rhythm of 24.9h
- despite exposure to social cues, his sleep cycle can’t adjust
- has to take sedatives and stimulants to keep pact with 24h
EZ not as influential bio rhythm as EP since it took a bio change for him to adjust to 24h day
Age Related Insomnia
evidence of poor quality sleep when old
Duffy et al
- may be due to natural changes in circadian rhythm
- can resist in sleep earlier and a broken sleep at night
- medication to increase melatonin
VS Age Related Insomnia
Hood et al
- management of insomnia improved if elderly were more active and exposed to light
Suggest EZ are more responsible for the changes in sleep patterns with age
Interactionist System
EP can’t be studied in isolation
- unlikely to be without EZ
Siffre
- artificial light, bio clock influenced by light EZ
EZ and EP interact, so no sense to seperate them
