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Infradian and Ultradian Rhythms Essay Plan
1. Describe in detail monthly cycles- regulate ovulation, the pituitary gland release hormones
FSH and LH which stimulate a follicle in one ovary to ripen an egg as well as trigger the
release of the hormone oestrogen, once egg ripened, ruptured follicle starts to produce
progesterone causing the lining of the womb to prepare for a pregnancy by increasing its
blood supply, two weeks after ovulation, no pregnancy- progesterone is reduced and the
lining of the womb shed. Empson looked at 21 male participants and measured their body
temperatures and alertness levels over periods varying from 49 to 102 days. He found some
evidence in males for a periodic variation of both body temperature and subjective ratings of
morning alertness, with a cycle length of approximately 20 days.
2. Describe SAD- depressed during the winter months, melatonin and serotonin produced
when it is dark, by the pineal gland, lack of these hormones can cause depression. Sleep
stages- five stages of sleep, first 4 NREM and 5th stage REM sleep, lasts about 90 minutes.
Stage 1 and 2 are light sleep, there's a change in electrical activity of the brain, alpha waves
and theta waves. Stages 3 and 4 shown by delta waves (SWS), hard to wake someone up
and most repair work is undertaken-production of growth hormones. REM sleep- fast,
desynchronised EEG activity resembling the awake brain.
3. Critical Point 1: There is a problem with the studies on REM sleep. There is the assumption
that it is dreaming sleep. Dermont and Kleitman found that participants were highly likely to
report dreaming when their brain waves resembled REM sleep. Although, they also found
that dream were recorded outside REM sleep and that sleepers, when awoken in REM sleep,
were not always dreaming. As a result of this, this makes it difficult to identify dreaming as it
is based on the assumption that REM sleep equals dreaming.
4. Critical Point 2: There is a flaw to the explanation that monthly cycles are just governed by an
endogenous system. Russell found that women's menstrual cycles synchronise with each
other if they live with each for a given period of time. Consequently, this implies that the
synchronisation of menstrual cycles can be affected by pheromones. Therefore, supporting
the view that external cues could have an effect on monthly cycles.
5. Critical Point 3: A key consequence of the menstrual cycle is PMS. There has been evidence
to show that it is not just a psychological problem but a physiological one as well. Dalton
found that PMS was associated with an increase in accidents, lower achievement
academically, suicides and crime. However, there is a positive application of the research into
PMS, it can be used as a legal defence. For example Johnson reviewed a case study about a
Ms English drove her car into her married lover after an argument, killing him. She was
charged with murder but eventually put on probation because it was argued in court that her
actions were related to severe PMS. Therefore, this research has helped women avoid jail
because of a biological disorder that they cannot control.
6. Critical Point 4: On the otherhand, there is evidence we can "will" our biological rhythms to
change. Born found that people who were told to wake up at earlier times of the night than
usual had higher levels of the stress hormone ACTH than normal at the designated time and
they woke up earlier. Consequently, it is difficult to say that it is just biological factors
controlling our bodies, there are external influences as well.
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Critical Point 5: There is a positive application for the discovery of SAD, phototherapy has
been developed. A study by Eastman found that a placebo condition was less effective than
the phototherapy. As a result of this, this has helped people with this disorder to get rid of it.…read more