Infradian and Ultradian rhythms Flashcards
What is an example of a infradian rhythm?
The menstrual cycle
What is the menstrual cycle governed by?
Monthly changes in the hormone levels which regulate ovulation
How long is the menstruation cycle?
Usually 28 days - time between the first day of the cycle to the day before the next cycle
What happens during each menstrual cycle?
Rising levels of the hormone oestrogen causes the ovary to release an egg
What happens after ovulation?
The hormone progesterone helps the womb lining grow thicker and if pregnancy doesn’t occur the egg is absorbed into the body
Despite menstruation being an induction cycle what does research suggest?
It may be influenced by exogenous factors such as cycles of other women.
What was Stern and McClintock’s research?
Demonstrated how menstrual cycle is synchronised as a result of the influence of female pheromones
It involved 29 women with a history of irregular periods. Samples of pheromones were taken from nine of the women at different stages in their cycles via cotton pad in arm pit. The pads were treated with alcohol and frozen to be rupped on upper lip of participants. On day one pads from start of menstrual cycle applied to all 20 women - results = 68% found their cycle changed closer to the cycle of the donor
What is Seasonal Affective Disorder?
A depressive disorder which has a seasonal pattern of concept - it is described and diagnosed as a mental disorder in DSM5
What are symptoms of SAD?
Like other forms of depression main symptoms = persistent low mood, lack of interest in life
When is SAD often triggered?
During the winter months when the number of daylight hours become shorter
What type of rhythm is SAD?
A particular type of Infradian rhythm called a circannual rhythm as it is subject to a yearly cycle
How can SAD also be classes as a circadian rhythm?
It may be due to the disruption of the sleep wake cycle and this can be attributed to prolonged darkness during winter
What hormone have psychologists implicated in the cause of SAD?
Melatonin - as at night the penal gland secretes melatonin until dawn but during winter the lack of light means the secretion process continues for longer which is thought to have a knockon effect on the production of serotonin in the brain - linked to the onset of depression
What have psychologists identified within the sleep cycle?
Five distinct stages of sleep that together span approximately 90 minutes and the cycle continues throughout the night.
What is each stage of sleep characterised by and how is it monitored?
A different level of brain wave activity and can be monitored using an EEG
