biological rythms:infradian and ultradian

Question 1

key features of menstrual cycle

Answer 1

-infradian rhythm
-governed by monthly hormone level changes
-takes approximately 28 days to complete cycle
-rising levels of oestrogen cause ovary to develop egg and release(ovulation)
-progesterone helps womb lining grow thicker
-if pregnancy doesnt occur period comes.

Question 2

what was Mclintoks study?

Answer 2

-studied 29 women with irregular periods
-samples of pheomones taken
-cotton pad placed up armpit
-then treated with alcohol and frozen
-rubbed on upper lip of other Ps

Question 3

what was MCclitoks findings?

Answer 3

-68% of women experined changes to cycle closer to the odour doners.

Question 4

what are strengths of infradian rhythms?

Answer 4

(evolutionary basis)
-advantage for women to menstrate tg
-become pregnant at the same time
-allow babies who lost their mother during or after childbirth to have breast milk
-improving survival

Question 5

weaknesses of infradian rhythms?

Answer 5

(methodological limitations)
-other factors can affect periods e.g diet, excercise, stress
-these are confounding variables
-so supposed pattern of synchronisation is no more than would hv been expected by chance
-studies can be flawed

Question 6

what is seasonal affective disorder?

Answer 6

• depressive disorder
  -low mood, low interest in life
  -daylight hrs become shorter (winter blues)
  -circannual rythm
  -can be classed circadian rythm as it can be due to disruption of the sleep wake cycle
  -due to daily darkness in winter

Question 7

strengths of reserach into SAD?

Answer 7

-light box therapy
-stimulates strong light to reset internal body clock
-reduces SAD effects in ab 80% of people
-regarded as safe

Question 8

counterpoint research into SAD?

Answer 8

-light therapy may produce headaches and eye strain
-relapse rate of 46% over sucessive winters comapred to 27% in comaprison with grp doing CBT

Question 9

what hormone has been associated within SAD?

Answer 9

-hormone melatonin is implicated in the cause of SAD
-pineal gland secrets melatonin until dawn when light increases
-but during winter the lack of light means melatonin secretion process is longer
-knock on effect on serotonin

Question 10

what is an ultradian rhythm

Answer 10

-e.g stages of sleep
-5 distinct stages lasting approxmately 90 mins

Question 11

what is stage 1 and 2 of stages of sleep?

Answer 11

-may be easily awoken
-stage 1= has high brainwave frequency and short amplitude
-alpha waves
-stage 2= alpha waves continue w occasional random changes called sleep spindles

Question 12

what is stages 3 and 4?

Answer 12

-deep sleep or slow wave sleep
-delta waves w low frequency and high amplitude
-hard to wake someone up

Question 13

what is stage 5 of the sleep? (REM sleep)

Answer 13

-body paralysed
-brain activity represents an awake brain
-theta waves
-eyes occasionally move
-thus rapid eye movement (REM)
-dreams most often experienced

Question 14

strengths of ultradian rythms?

Answer 14

(improved understanding)
-growth hormone mostly produced during SWS therefore redcued in older ppl
-cauter et al= resulting sleep deficit may explain various issues in old age
-e.g reduced alterness
-to increase SWS relaxation and medication can be used

Question 15

weakness of ultradian rythms?

Answer 15

(individual differences)
-tucker et al found differences in Ps in terms of sleep duration of each sleep stage
-in particular in stages 3 and 4
-differences may be biologically determined
-normal sleep therefore hard to define

Question 16

how can we evaluate use of sleep labs?

Answer 16

-controls EVs
-exclude temporary variables such as noise or temp which can affect sleep

BUT they are attached to complicated machinery so doesnt reprsent ordinary sleep patterns