Biological Rhythms: Infradian and ultradian rhythms
- Created by: zoe_chetty
- Created on: 25-01-19 14:32
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Infradian and ultradian rhythms
Infradian rhythms
- The menstrual cycle
- The female menstrual cycle, an example of an infradian rhythm, is governed by monthly changes in hormone levels which regulate ovulation
- The cycle refers to the time between the first day of a woman's period, when the womb lining is shed, to the day before her next period (28 days)
- Oestrogen causes the ovary to develop an egg and release it
- After ovulation, progesterone helps the womb lining to grow thicker,readying the body for pregnancy
- If pregnancy does not occur, egg is absorbed into body and womb lining comes away and leaves body
- Research study
- Although the menstrual cycle is an endogenous system, evidence suggests it may be influenced by exogenous factors such as the cycles of other women
- McClintock used 29 women with a history of irregular periods
- Samples of pheromones were gathered from 9 of the women at different stages in their cycles, via a cotton pad placed in their armpit
- Pads treated with alcohol and frozen, to be rubbed on the upper lip of other ppts
- On day one, pads from the start of the cycle were applied to all 20 women
- Day 2, all given pad from second day of cycle
- 68% of women experienced changes to their cycles which brought them closer to the cycle of their 'odour donor'
- Seasonal affective disorder
- SAD is a depressive disorder which has a seasonal pattern of onset
- Often referred to as the winter blues as the…
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