BIOLOGICAL RHYTHMS - CIRCADIAN RHYTHMS Flashcards
(35 cards)
what 4 things must we remember for circadian rhythms?
biological rhythms
sleep/wake cycle
siffre’s cave study
other research
what are biological rhythms?
distinct patterns of changes in body activity to cyclical time periods influenced by exogenous zeitgebers and endogenous pacemakers
what is a circadian rhythm?
a biological rhythms subject to a 24 hour cycle regulating a number of body processes such as sleep/wake cycle and changes in the core body temperature
who has biological rhythms?
plants animals and people
why 2 things are biological rhythms governed by?
body’s internal biological clock - endogenous pacemakers
changes in the environment - exogenous zeitgebers
what is the most important exogenous zeitgeber?
daylight and this is shown through how we feel drowsy when it’s night-time and alert during the day
what is ‘free-running?’
if the biological clock was left to it’s own devices without the influence of external stimuli such as light
who tried to answer the question of ‘free-running’ and conducted research?
Siffre
what dud Siffre do?
spent several extended periods underground to study the effect of his bio rhy
what was siffre deprived of, and what did he have access to?
deprived of exposure to natural light and sound
access to adequate food and drink
how long did he spend in first 2 studies in the cave?
- 2 months in the cave of the alps
2. 10 years later, performed similar test for 6 months in a Texan cave
what happened in both of Siffre’s experiments?
‘free-running’ biological rhythm settled down to 25 hours though he did continue to fall asleep and wake on a regular schedule
who found similar results to Siffre?
Aschoff and Wever
what did Aschoff and Wever do?
ppts spent 4 weeks in WWII bunker w/ no natural light
what were the findings of Aschoff and Wever experiment?
all but 1 ppts had circadian rhythm of 25 hrs, one had 29 hrs
what do Siffre’s and Aschoff and Wever’s study show?
‘natural’ sleep/wake cycle could be longer than 24 hours, but trained by exogenous zeitgebers associated w/ 24 hrs day
who studied exogenous zeitgebers?
Folkard et al
who did Folkard et al study and what did they do?
12 ppl who agreed to live in a dark save for 3 weeks, went o be at 11:45 and waking up at 7:45
what did researchers to over the course of Folkard’s study?
gradually speeded up the clo9ck so the 24 hr day was eventually 22 hrs
what were the findings of Folkard’s study and what does this suggest?
only 1 ppt adjusted by to the new regime , suggested the existence of a strong free-running circa rhy cannot be easily overridden by exogenous zeitgebers
give 3 evaluations points for circadian rhythms?
+ practical application to shift work
+ practical application to drug treatments
- use of case-studies and small samples
a strength of circadian rhythms is that it has good practical application to…
shift work
what does knowledge about circadian rhythms given researchers a better understanding of?
adverse consequences that can occur as a result of their disruption known as desynchronization
what did Boivin et al find that shows affects of shift work?
night workers engaged in shift work experience a period of reduced concentration around 6 in the morning, a circadian trough that makes mistakes and accidents more likely
