Biological rhythms: Circadian rhythms Flashcards
1
Q
What are our internal clocks called
A
- endogenous pacemakers
2
Q
What are the external changes in the environment called
A
- exogenous zeitgebers
3
Q
What is the term used for rhythms that occur many times during the day
A
- ultradian rhythms
4
Q
What is the term used for rhythms that take longer to complete
A
- infradian rhythms
5
Q
What is the term used for rhythms longer than an infradian rhythm
A
- circannual rhythms
6
Q
What is an important exogenous zeitgeber
A
- daylight
7
Q
Outline Siffre’s cave study
A
- Siffre’s spent several extended periods underground to study the effects of his own biological rhythms
- first in the Southern Alps for 2 months
- then for 6 months in a Texan cave
- his ‘free-running’ biological rhythms extended to 25 hours, falling asleep and waking up around the same times
8
Q
Outline Aschoff and Wever’s study
A
- convinced a group of ppts to spend 4 weeks in a WW2 bunker deprived of natural light
- most ppts’ circadian rhythms extended to 29 hours, only one displayed an around normal circadian rhythm of 25 hours
- this suggests the normal sleep/wake cycle may be slightly longer than 24 hours but because of exogenous zeitgebers we have been trained to follow one of 24 hours
9
Q
Give a strength of this explanation
A
- it has had practical applications to shift work
- Night workers engaged in shift-work experienced a period of reduced concentration around 6 in the morning, meaning mistakes and accidents are more likely
- shift workers are also three times more likely to develop heart disease, thus research into the sleep/wake cycle may have economic implications in terms of how best to manage worker productivity
10
Q
What is a weakness of this explanation
A
- studies tend to involve smaller groups of ppts, these ppl may not be representative of the wider population and this limits the extent to which meaningful generalisations can be made
