Biopsychology- Biological Rhythms Flashcards
How often do circadian rhythms occur?
Once every 24 hours
What is an example of a circadian rhythm?
The sleep-wake cycle
How often do infradian rhythms occur?
Less than once every day
What is an example of an infradian rhythm?
The menstrual cycle
How often does an ultradian rhythm occur?
More than once every 24 hours
What is an example of an ultradian rhythm?
The sleep cycle
What is an endogenous pacemaker?
Genetically determined biological structures and mechanisms within the body
What is the superchiasmatic nucleus?
Part of the hypothalamus that acts as an internal clock to keep the body on an approximate 24-hour sleep-waking cycle
What does the superchiasmatic nucleus do?
It is sensitive to light and regulates the pineal gland which secretes melatonin (a hormone which induces sleep)
What are exogenous zeitgebers?
Influences outside of the body that act as a prompt which may trigger a biological rhythm
How did Siffre demonstrate how light is the most important zeitgeber?
He spent 6 months in a cave with no clocks and no natural light- his sleep-wake cycle extended from 24 hours to 25-30 hours
