biopsychology - 1.7 Flashcards
(27 cards)
cycle
a series of events that happen in the same order continuously
biological rhythm
when processes in the body follow a cycle e.g. body temperature
circadian rhythm
any biological rhythm that repeats every 24 hours
e.g. sleep wake cycle, body temperature
describe an example of the sleep-wake cycle
wake up around 7am
feel most alert at 11am
dip in alertness in the evening
asleep at 11pm
least alert at 2am
describe the body temperature cycle
lowest body temp around 4am
highest body temp around 6pm
strength of circadian rhythms (application)
chromotherapeutics - method of delaying action of drugs until the time of day at which they are most effective
it was developed using knowledge of circadian rhythms
allows people to take drugs which then aren’t effective until necessary, hours later
limitation of circadian rhythms (individual difference)
drugs assume everyone’s circadian rhythms are the same
Duffy (2001) conducted a controlled observation into participants sleep-wake cycles which lasted a month
carefully controlled extraneous variables like noise and light
found 2 types of people
morning people up around 6am and asleep around 10pm, highest body temp around 5pm
evening people up around 10am and asleep around 1am, highest body temp around 8pm
she found individual differences in the timings of people’s circadian rhythms
ultradian rhythm
any biological rhythm that takes less than 24 hours to complete e.g. 5 stages of sleep
stage 1 sleep
just starting to fall asleep and can be easily woken up by noises or other disturbances
probably still aware of some things going on around you
muscles stop moving and eyes slowly move behind eyelid
stage 2 sleep
heart rate slows down and body temperature drops
actually fully asleep and not aware of surroundings
eye movements either slow or stop completely
stage 3 sleep
brain waves slow down with only a few bursts of activity
deep sleep where muscles relax
this stage is difficult to awaken from and you may feel disoriented if something wakes you up
stage 4 sleep
even deeper sleep
brain waves further slow
very hard to wake
tissue repair occurs and hormones are released to help with growth
stage 5 REM sleep
the cycle where we dream
eyes move rapidly behind lids
breathing becomes shallow and rapid
blood pressure and heart rate increase
how long does each sleep cycle approximately last for
90 minutes
how many sleep cycles would occur in 7-8 hours of sleep?
5 to 6
basic rest activity cycle (BRAC)
one cycle lasts 90 minutes
ultradian rhythm of alertness
what can the BRAC be applied to?
can help explain why professional musicians and athletes break up their performance into short segments and why working days have breaks
limitation of ultradian rhythms (individual differences)
Tucker et al. (2007) monitored people’s sleep across a period of 3 weeks in his lab
controlled extraneous variables
measured time spent by participants in different stages
individual differences were greatest for the time spent in deep sleep
study showed that ultradian rhythms can vary between different people
infradian rhythm
any biological rhythm that lasts more than 24 hours
e.g. hibernation and menstruation
menstrual cycle
controls the release of oestrogen and progesterone across a 28 day cycle
it controls a woman’s fertility and ovulation
seasonal affective disorder (SAD)
people experience seasonal variations in their mood
could have depression when days are shorter and darker
cycle repeats every year
example of infradian rhythm
limitation of infradian rhythms (individual differences)
length of menstrual cycle is 28 days, but it varies across different women
cycle can vary from 23 days to 36 days
in teenage girls the cycle can vary from 21 days to 45 days
women with shorter cycles will have more cycles a year
pacemaker
structures within our body that control the timing of biological rhythms
hormone
a chemical messenger that is released into the bloodstream by glands and travels to target areas
