Biopsychology: Biological Rhythms (Circadian, Infradian & Ultradian) Flashcards
What is an ultradian rhythm with an example?
A cycle less than 24 hours e.g. the stages of sleep
Define the term circadian rhythm and give an example.
A cycle that lasts for 24 hours e.g. sleep-wake cycle
Define the term infradian rhythms and give an example.
A cycle that lasts longer than 24 hours e.g. the menstrual cycle
What is meant by the term endogenous pacemaker?
Internal body clock
What is meant by the term exogenous zeitgeber?
External factors that influence the body clock
Name the main endogenous pacemaker in the sleep-wake cycle.
Suprachaismatic Nucleus (SCN)
In the sleep wake cycle, when it goes dark less light is received by the …
Retina
What does the SCN stimulate?
The pineal gland
What is released by the pineal gland to promote sleep?
Melatonin
Name an exogneous zeitgeber is the sleep-wake cycle
Light
Clocks
Siffre spent six months in a cave. What happened to his circadian rhythm?
It went from 24 hours to a 25 hour cycle
What is a problem with Siffre’s research?
Low population validity - case study
Lacks ecological validity - unlike real life
Explain what Wever did and why it supports Siffre.
Wever conducted research over 400 times where people were in an underground bunker with a free running rhythm
Supports Siffre as they developed a 25 hour cycle showing role of endogenous factors
How long does the menstrual cycle last?
28-35 days
What happens on the first day of the menstrual cycle?
Womb lining is shed
What does the pituitary gland release during the menstrual cycle?
FSH