First 669 words of the document:
Outline one example of a circadian rhythm
A circadian rhythm is a biological rhythm that's happens every 24 hours. An example of a circadian
rhythm is the sleep-wake cycle. Every day we will sleep and we have adapted to this over time as
generally speaking we are awake in the morning and asleep at night. Exogenous zeitgebers and
endogenous pacemakers work together to control this biological clock, to keep the cycle in-sync
adjusting the inherited genetic clock with the environment by sensing when it is light through
communication between the pineal gland and SCN, producing hormones such as melatonin to make us
sleep. It is also shown that we will still go through the 24hr sleep wake cycle when our environment
changes and there are no external factors, showing that our bodily functions are controlled inside in
24 cycles. Supporting this, the SCN, when in petri dish still works in a 24.5 hour cycle!
Outline and evaluate one or more explanations for sleep disorders.
Explanations of sleep disorders tend to have a behavioural and biological theory to explain them.
Insomnia is one of them that has many genetic factors as well as environmental.
Insomnia is a sleep disorder where you basically are unable to sleep. There are two types of
insomnia, primary and secondary. Primary insomnia is the illness itself. The sleeplessness is not
caused by a medical, psychiatric or environmental cause. This sleeplessness would have to last at
least one month, does not occur purely during other sleep disorders such as narcolepsy and is not
because of possible physiological effects from using drugs and medication. If there are other
underlying causes to the disorder, it would then be secondary insomnia where a psychiatric
(depression) or medical disorder (chronic pain) causes the sleeplessness. They range from causes
such as hormone changes, asthma, stimulants and temperature etc.
As I said earlier, primary insomnia is the illness itself and is not affected by medical and environmental
causes. This leads us to believe if it is a disorder, if there is any biological research to show that
insomnia is genetic.
Dauvilliers did a study on chronic insomniacs to see if there was a link between them and their close
family. After asking 256 repeated primary insomniacs to complete psychometric questionnaires,
questionnaire about their family history, a clinical interview (and even a polysomnography in order to
collect physiological recordings of the participant's sleep) and using a control group to find an
estimated base-rate incidence of insomnia in their families to understand what all the various data
meant, he found a higher percentage in participants with primary insomnia reported familial insomnia
compared with the non-insomnia control group. This research suggests a familial link to primary
insomnia. This study collected a lot of data from numerous measures as well as using a large sample
of chronic insomnias (who are sufferers of insomnia for a long period of time) and a control group,
suggesting that the data collected is reliable. But do we really understand what it means, what does
it actually show about insomnia? There is little scientific proof that this link exists, it all lies on the fact
that the participants believe it's in their family history.
In order to prove that sleep disorders and insomnia are biological we must look at other research to
show there is some evidence of this. Insomnia is inability to sleep; this suggests a problem with our
sleep-wake cycle. It is a circadian rhythm affected by endogenous pacemakers as well as exogenous
zeitgebers. We are able to adjust to our environment relatively well but if something happened to
our endogenous pacemakers, this could result in a sleep disorder.
Idiopathic insomnia supports this hypothesis. It occurs due to brain abnormalities in mechanisms that
Other pages in this set
Here's a taster:
control the sleep-wake cycle. Normally this tends to occur in children but if the sleeplessness
becomes trouble for the rest of their lives, it is attributed to an abnormality in the neurologic control
of the sleep-wake cycle as it creates problems promoting wakefulness/sleep because it affects the
brain reticular system and media forebrain.
There is physiological research that supports the idea that there is an abnormality with biological
components that are involved in sleeping.…read more
Here's a taster:
suggesting that older people are more likely to suffer from insomnia. However, I think that melatonin
production in itself could be a biological explanation because it is a hormone that is affecting our
sleep-wake cycle. Just as children may have brain abnormalities which affect their sleep patterns,
some people could be born/develop lack of this hormone or unable to produce sufficient amounts.
This could be treated by sleeping pills which contain the previously deprived hormone.…read more