Biological rhythms Flashcards
What is an Endogenous Pacemaker?
An internal mechanisms known as our body clocks that govern internal rhythms.
What is an example of an Endogenous Pacemaker.
The Suprachiasmic nucleus is the master clock responsible for sleep and arousal, by sending signals to the pineal gland.
What is an Exogenous Zeitgebers?
External, environmental events that are responsible for resetting the biological clock of an organism.
What is an example of a exogenous zeitgeber
Meal times, Social activities and light resets the body clock daily.
Decoursey research supporting endogenous pacemakers.
They destroyed the SCN of 30 chipmunks (unable to generalise), (ethical), (cause and effect), and found that when returned to the wild, the sleep cycle disappeared and many died as they were awake when they should be asleep.
Mutant Hamsters supporting endogenous pacemakers
Hampsters with a 20 hour sleep cycle had their SCN transplanted into normal hamsters, who adapted the same behaviour. (ethical, can’t generalise, no cause and effect)
Innuit Indians research supporting endogenous pacemakers
Living in the Arctic circle there is hardly any dark in summer nor any light in winter. If controlled by EZ’s, they would sleep all winter and not in summer, but this isn’t the case. (small sample cannot be generalised).
Boivin (1996) supporting exogenous zeitgebers
Night workers who are engaged in work for a long period of time reduced concentration around 6AM and often had accidents around this time. (individual differences play a role)
Campbell and Murphy (1998) supporting exogenous zeitgebers
15 participants had light shone behind their knees waking them up up to 3 hours earlier. (small sample).
Laughton Miles supporting exogenous zeitgebers
A young man blind from birth’s sleep cycle could not be adjusted, and had to take sedatives at night and stimulants in the morning. (small sample), (blindness may bring other issues)