biological rhythms: circadian rhythms Flashcards
1
Q
what is a biological rhythm
A
an influence on the way the body system behaves
2
Q
what are biological rhythms governed by
A
- endogenous pacemakers
- exogenous zeitgeber
3
Q
what is the sleep/wake cycle
A
- daylight makes us feel drowsy when its nighttime and alert during the day
- SCN provides information from the eye about light
4
Q
when was sittres cave study
A
1962
5
Q
sittres cave study (1962)
A
- spent time in caves to study his own biological rhythm
- deprived of natural light and sound
- spent 2 months underground and his biological rhythm settled on 25 hours which made him believe that he had only been underground for 1 and a half months
6
Q
when was aschoff and wever study
A
1976
7
Q
aschoff and wever (1976)
A
- 26 participants spent 4 weeks in a ww2 banker and were deprived of natural light
- 1 participants sleep cycle extended to 29 hours
- the rest had a circadian rhythm between 24 and 25 hours
8
Q
when was folkard et al study
A
1985
9
Q
folkard et al study(1985)
A
- 12 participants lived in a dark cave for 3 weeks
- slept form 11:45pm to 7:45am
- the clock was gradually sped up so that 24 hours became 22
- only 1 participant adjusted
- the existence of a strong free running circadian rhythm cannot be easily overridden by external factors
10
Q
strengths of circadian rhythm
A
- shift workers
- make more mistakes at 6am (boivin et all 1996)
- 3 times more likely to get heart attacks - medical treatment
- coordinate the body’s heart rate, digestion and hormone levels
- chronotherapeutics
- aspirin for heart attacks are most effective taken at night
11
Q
limitations of circadian rhythm
A
- individual differences
- generalisations are difficult to make
- studies have very small sample sizes
- sleep wake cycles vary from 13 to 65 hours (czeisler et al)
