Infradian and Ultradian Rhythms

Question 1

infradian rhythms

Answer 1

last longer than 24hrs, but shorter than a year e.g. menstrual cycles

Question 2

Ultradian rhythms

Answer 2

shorter than 24 hrs and repeats itself e.g. stages of sleep which last 90 minutes

Question 3

Stern and McClintock

Answer 3

• menstrual cycle influenced by exogenous factors
• used pheromones from women with regular periods and rubbed it on women with irregular periods
• 68% of women had their cycle synced with their donors

Question 4

SAD

Answer 4

• psychologists hypothesise that sad is caused by increased melatonin inhibiting the binding of serotonin
• assumes that depression has an entirely biological basis

Question 5

sleep stage 1 & 2

Answer 5

• light sleep
• high frequency and short amplitude brain waves
• muscle activity slows
• non- rem (stage 2-3)

Question 6

sleep stage 3 & 4

Answer 6

• deep sleep
• slow wave sleep
• Delta brain waves with low frequency and high amplitude
• growth hormones start to be released

Question 7

stage 5

Answer 7

• REM sleep (rapid eye movement)
• body paralysed but brain activate resembling being awake
• theta waves produced, we report having dreams
• memory consolidation and protein synthesis, brain being restored

Question 8

strengths of infradian rhythms

Answer 8

EVOLUTIONARY BASIS
- synchronisation of menstrual cycles thought to have some evolutionary value
- get pregnant together, share responsibilities of childcare increasing survival

PRACTICAL APPLICATIONS FOR SAD
- Eastman et al. phototherapy relieves depressive symptoms in 60% of patients
- research led to effective treatments targeting underlying bio causes