Biological Rhythms: Infradian and Ultradian Rhythms
- Created by: Georgia O'Keeffe
- Created on: 08-05-17 17:38
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- Biological Rhythms: Infradian and Ultradian Rhythms
- Infradian Rhythms
- a type of biological rhythm with a frequency of less than one cycle in 24 hours.
- female menstrual cycle - rise in oestrogen causes ovary to develop an egg, progesterone causes womb lining to grow thicker
- McClintock showed how menstrual cycles synchronise when influenced by female hormones
- 29 women with irregular periods - 9 women gave their pheromones via cotton pad under armpit
- pads were rubbed on upper lip other pps - 68% experienced changes to their cycle
- 29 women with irregular periods - 9 women gave their pheromones via cotton pad under armpit
- SAD - depressive disorder with a seasonal pattern of onset. Melatonin is implicated and can affect production of serotonin in the brain
- is an infradian rhythm called a circannual rhythm as it is subject to a yearly cycle
- Ultradian Rhythms
- a type of biological rhythm with a frequency of more than one cycle in 24 hours
- Sleep/wake cycle - 5 distinct stages of sleep that altogether span approx 90 mins.
- Stages 1 and 2 - light sleep, easily woken, brainwave patterns become slower and more rhythmic
- Stages 3 and 4 - involve delta waves which are slower and have a greater amplitude, slow wave sleep
- Stage 5 - aka REM sleep, the body is paralysed yet brain activity speeds up
- Evaluation
- menstrual synchrony is thought to have evolutionary value
- it can be advantageous for females to menstruate together
- criticisms have been made of early synchronisation studies and the methods employed. Confounding variables eg stress may affect a womans cycle
- research typically involves small samples of women and relies on pps self reportong the onset of their own cycle
- Dement and Kleitman found that REM activity highly correlated with the experience of dreaming
- also suggests that REM is an important component of the ultradian sleep/cycle
- menstrual synchrony is thought to have evolutionary value
- Infradian Rhythms
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