Biological rhythms Flashcards
(18 cards)
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 Suprachiasmatic 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 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
Hamsters with a 20 hour sleep cycle had their SCN transplanted into normal hamsters, who adapted the same behaviour.
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.
Campbell and Murphy supporting exogenous zeitgebers
15 participants had light shone behind their knees waking them up up to 3 hours earlier.
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.
Weaknesses of Laughton Miles
Small sample, Blindness may bring other issues
What is a circadian rhythm
A rhythm that takes 24 hours to complete
Example of circadian rhythm
Sleep/Wake cycle
What is an Infradian rhythm?
A rhythm that lasts longer than a circadian rhythm (24 hours).
What is an example of an Infradian rhythm
The menstrual cycle has four stages: Ovulation and Menstrual, which take up to 28 days to fully complete.
What is an Ultradian rhythm?
A cycle that takes place more than once in 24 hours.
Example of Ultradian rhythm
Digestion
Real world application of circadian rhythm
Chromotherapy is the administration of drugs at times determined by the body’s circadian rhythm.
Real world application of infradian rhythm
Photo therapy gives individuals a lightbox that stimulates light in the morning and evening that rests their melatonin levels. The debilitates symptoms of Seasonal Affective Disorder.
