Biological rhythms: ultradian rhythms

Question 1

ultradian rhythm definition

Answer 1

biological rhythm with a frequency of more than one cycle in 24 hours (takes less than one day) such as the stages of sleep

Question 2

what is one of the most insensitively researched ultradian rhythms

Answer 2

sleep cycle

Question 3

what is the sleep cycle

Answer 3

5 distinct stages of sleep that altogether last for 90 mins and continues throughout the night

Question 4

how is each stage of the sleep cycle characterised

Answer 4

different level of brainwave activity

Question 5

how is brainwave activity monitored

Answer 5

using and EEG

Question 6

what types of brainwaves is in stage 1

Answer 6

alpha waves

Question 7

what types of brainwaves is in stage 3

Answer 7

delta waves

Question 8

what types of brainwaves is in stage 2

Answer 8

alpha waves but occasional change in pattern called sleep spindles

Question 9

what types of brainwaves is in stage 4

Answer 9

delta waves

Question 10

what types of brainwaves is in stage 5

Answer 10

theta waves

Question 11

stage 1 and 2 of sleep cycle

Answer 11

-light sleep where person can be easily woken
-alpha waves which have a high frequency and short amplitude
-during stage 2 these alpha waves continue but there are occasional random changes in pattern called sleep spindles

Question 12

stage 3 and 4 of sleep cycle

Answer 12

-deep sleep or slow wave sleep (SWS)
-brain waves are delta waves which have a lower frequency and higher amplitude
-difficult to wake someone at this point

Question 13

stage 5 of sleep cycle

Answer 13

-body is paralysed but brain activity closely resembles that of an awake brain
-theta waves are produced and the eyes occasionally move around which is called rapid eye movement (REM)
-dreams are most often experienced during REM sleep, but can also occur in deep sleep

Question 14

strength of ultradian rhythms - improved understanding

Answer 14

-research into ultradian rhythms has improved understanding of age-related changes in sleep
-sleep scientist have observed that the SWS reduces with age. growth hormone is mostly produced during the SWS (slow wave sleep) and therefore this is reduced in older people. Van Cauter et al 2000, resulting sleep deficit may explain various issues in old age, such as reduced alertness. in order to increase SWS, relaxation and medication may be used –> suggests knowledge of ultradian rhythms has practical value

Question 15

limitation of ultradian rhythms - individual differences

Answer 15

-significant variation between people
-Tucker at al 2007 found larger differenced between participants in terms of duration of each sleep stage, particularly stages 3 and 4. Tucker et al suggest that these differences are likely to be biologically determined –> makes it difficult to describe ‘normal sleep’ in any meaningful way

Question 16

evaluation of ultradian rhythms - the sleep lab

Answer 16

-benefit of conducting studies in lab settings is control of extraneous variables. means that a researcher can exclude temporary variables such as noise or temperature that may affect sleep
-however, lab studies involve being attached to complicated machinery, leading to participants to sleep in a way that does not represent their ordinary sleep patterns