Endogenous Biological Rhythms
Circadian Rhythms
Occur about every 24 hours.
Example:The sleep-wake cycle.
Infradian Rhythms
Occur less often than once a day.
Examples include birds migrating, bears hibernating.
Ultradian Rhythms
Occur more frequently than once a day, about every 90min.
Examples include stomach contractions and hormone levels.
Circadian Rhythms
Occur in plants, animals, insects and people.
To study endogenous circadian rhythms, scientists isolate volunteers from time cues.
Supraciasmatic nucleus (SCN)
Located in the hypothalamus, responsible for circadian rhythms by regulating melatonin, a hormone secreted by the pineal gland.
When Internal Clocks are Out of Sync
Internal desynchronization
A state when biological rhythms are not in phase with one another.
Circadian rhythms are influenced by changes in routine. Examples include:
Airplane flights across time zones.
Adjusting to new work shifts.
Also, illness, stress, fatigue, excitement, drugs, and mealtimes
2006-09-10 10:22:35
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answer #1
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answered by Peakles 3
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I'd love to....some other time perhaps (shortly after my visit to the reference library probably)
2006-09-10 10:18:12
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answer #2
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answered by Anonymous
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