Biological Rhythms: Ultradian Rhythms

Question 1

Ultradian Rhythms

Answer 1

More than one cycle in 24 hours

Question 2

Stages Of Sleep

Answer 2

• Sleep patterns occurs in 90-minute periods (more than one cycle in a day)
• Divided into 5 stages, each characterised by a different level of brainwave activity (monitored using an EEG)

Question 3

Stages 1 And 2 Of Sleep Cycle

Answer 3

Stages 1 and 2- Light sleep where a person may be easily woken. In stage 1, brain waves are high frequency and have a short amplitude. These are alpha waves. In stage 2, the alpha waves continue but there are occasional random changes in patterns called sleep spindles.

Question 4

Stages 3 And 4 Of Sleep Cycle

Answer 4

Stages 3 and 4- This is known as deep sleep or slow wave sleep (SWS). The individual waves now have lower frequency and higher amplitude. It is difficult to wake someone up at this point.Stages 3 and 4- This is known as deep sleep or slow wave sleep (SWS). The individual waves now have lower frequency and higher amplitude. It is difficult to wake someone up at this point.

Question 5

Stage 5 Of Sleep Cycle

Answer 5

Stage 5 (REM Sleep)- The body is paralysed yet brain activity closely resembles that of the awake brain. During this time, the brain produces theta waves and the eyes occasionally move around. Dreams most often experienced during REM sleep, but may also occur in deep sleep.

Question 6

A03 (Understanding Age-Related Changes In Sleep)

Answer 6

E- SWS reduces with age. Growth hormone is produced during SWS so this becomes deficient in older people. Van Cauter et al. suggest the reduced sleep may explain impairments in older age. SWS sleep can be improved using relaxation and medication.
E- This suggests that knowledge of ultradian rhythms has practical value.

Question 7

A03 (Individual Differences In Sleep Stages)

Answer 7

E- Tucker et al. found large differences between participants in the duration of stages 3 and 4. They suggest that these differences are biologically determined.
E- This makes it difficult to describe ‘normal sleep’ in any meaningful way.

Question 8

A03 (The Sleep Lab)

Answer 8

E- One of the benefits of conducting studies of sleep in lab settings is control of extraneous variables, such as noise or temperature that may affect sleep. However, lab studies involve participants being attached to complicated machinery, so their sleep does not represent their ordinary sleep patterns.
E- This dilemma means it might be best to conduct some studies in people’s own homes and compare patterns with records made in lab settings.