Biological Rhythms and Sleep

Unit 3 revision guide. 

HideShow resource information
Preview of Biological Rhythms and Sleep

First 67 words of the document:

Biological Rhythms & Sleep
Biological Rhythms: circadian, infradian & ultradian.
Endogenous Pacemakers & Exogenous Zeitgebers
The Disruption of Biorhythms: jet lag & shift work.
The nature of Sleep & Life Span Changes: sleep stages & the changes of the sleep
Functions of Sleep: restoration theory & evolutionary theory.
Explanations of Sleep Disorders: insomnia, narcolepsy & sleep walking.

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

Biological Rhythms-AO1
Circadian Infradian Ultradian
A circadian rhythm lasts for 24 An infradian rhythm lasts for more An ultradian rhythm lasts for less
hours. An example of this is the than 24 hours but less than a than 24 hours. An example of this
sleep-wake cycle. year. An example of this is the rhythm is the sleep stages or the
menstrual cycle. brain activity during sleep.…read more

Page 3

Preview of page 3

Here's a taster:

Miles et al: blind people show the Eastman treated patients with not take that matter into
same pattern as sighted people bright light or a placebo and found account.
therefore it must be due to an that those treated with a bright 3. Methodology: sleeping in
internal mechanism. light were more likely to respond an artificial environment
with a partial or full remission of with electrodes (EEG)
AO2 Evaluative Points: symptoms. means that the research
1. Individual differences: lacks ecological validity.…read more

Page 4

Preview of page 4

Here's a taster:

Endogenous Pacemakers:-
The Suprachiasmatic nucleus (SCN) is an endogenous pacemaker. The SCN is a cluster of nerve cells in the
hypothalamus. It receives information about light as it is located above the optic chiasma (even when our
eyes are closed). Stephan & Zucker found that when the SCN is lesioned, the circadian rhythm of
sleep/waking, body temperature and feeding becomes irregular.…read more

Page 5

Preview of page 5

Here's a taster:

How do we disrupt our biological rhythm?
Usually exogenous zeitgebers change gradually allowing us time to adjust however a rapid change disrupts
co-ordination between endogenous pacemakers and exogenous zeitgebers. This consequently means we
are not always able to function properly. A lack of synchrony within the environment might lead to health
problems and could affect cognitive function, altered hormonal function and gastrointestinal complaints.
Jet lag:-
Symptoms of jet lag include fatigue, disorientation and anxiety.…read more

Page 6

Preview of page 6

Here's a taster:

Real life applications: Czeisler et al studies shift workers in a factory. They found high illness rates,
sleep disorders and elevated levels of stress suggesting that their body clocks were out of sync. The
researchers suggested they move to a phase delay system of rotating shifts to reduce negative
effects. 9 months later workers were happier.
2. Gender Bias: most of the research only involves male participants as males tend to be more
involved in shift work.…read more

Page 7

Preview of page 7

Here's a taster:

Sleep and the lifespan:-
Infancy: babies sleep for about 16 hours a day but not continuously. They wake up every hour or so
and the cycle is shorter than an adults. They experience two types of sleep: active and quiet which
are versions of REM and SWS. Approximately half is spent in active (REM) because of their need for
growth. By about 6 months old most children have one main sleep-wake cycle with a few naps in
the day.…read more

Page 8

Preview of page 8

Here's a taster:

Theories of Sleep
Evolutionary (Ecological) Theory:-
Sleep is adaptive. It exists to promote survival and reproduction. Any behaviour or characteristics that
increase likelihood of survival and reproduction will be naturally selected and will survive as the animal
evolves. Each animal adapts their sleep pattern to their environment (ecological niche) for example dolphins
sleep for seconds at a time switching between hemispheres in order to survive.
Energy conservation: sleep is to conserve energy. Those with a high metabolism use more energy than
those with low metabolism.…read more

Page 9

Preview of page 9

Here's a taster:

Shapiro et al: runners of the marathon slept more the following days and NREM sleep increased
Dement: DJ wakethon for charity. Stayed awake for 201 hours (8days). 3 days in he became abusive.
5 days in he developed hallucinations. By the end of the wakethon his body temperature had
dropped and his brain was producing brain waves that were virtually undistinguishable from those of
a sleeping person.…read more

Page 10

Preview of page 10

Here's a taster:

Disorders of Sleep
Insomnia may relate to difficulties in going to sleep and/or staying asleep and may occur transiently,
intermittently or chronically (more than once a month).
Insomnia and its cause can be grouped into primary and secondary:
PRIMARY INSOMNIA: defined by DSM as a problem with no known cause which has occurred for
more than a month. It may be due to: bad sleep habits (e.g.…read more



Wow, really useful, thank you! 

Similar Psychology resources:

See all Psychology resources »See all resources »