Menstrual Cycle Flashcards
(15 cards)
What type of rhythm is the menstrual cycle?
Infradian rhythm
What is an infradian rhythm?
A biological process that repeats less frequently than once every 24 hours
What is another infradian rhythm?
Seasonal Affective Disorder
Takes a year to complete
Emotional mood lowers in winter and improves in summer
It is suspected it is due to the lack of bright sunlight in winter
What is the menstrual cycle?
28 day cycle with a 6 day period of fertility
Cycles can be shorter or longer- ranging between 24 and 35 days
What are the biological affects of the menstrual cycle?
• Releasing the egg (ovulation)
• Thickening of the womb lining
• Losing the womb lining during menstruation
How are the biological changes of the menstrual cycle regulated by hormones?
• Oestrogen pre-ovulation
• Progesterone post-ovulation
• Levels of these hormones act as EP’s, keeping the biological processes to time, acting as an internal body clock
What was McClintock’s procedure?
• Studied 135 women who lived in the same dormitory at university
- Recorded period onset and duration
What did McClintock find?
Women appeared to synchronise their cycles with their friendship groups
- Other researchers have found similar findings with women who cohabit
What was Stern and McClintock’s study investigating?
If synchronisation was due to women sharing pheromones
What was Stern and McClintock’s procedure?
20 women were given pads to wipe on their top lip each day
The pads had been taken from the armpits of 9 donor women at varying stages of their menstrual cycle
What was found in Stern and McClintock’s study?
The women would either shorten or extend their menstrual cycle to match the donor, depending on when in the donor woman’s menstrual cycle the pad had been collected
What do Stern and McClintock’s findings suggest?
Synchronisation due to the present pheromones, acting as an EZ as external cue for the timing of the infradian rhythm
While there have been researchers show similar results in synchronisation…
A number of studies have shown no synchronisation, including a study on cohabiting lesbian couples that did not synchronise despite optimal conditions for synchronisation
What is something not taken into consideration in the studies showing positive results for synchronisation?
Menstrual cycles can vary in length so women may appear to synchronise just due to variability in their cycles
What is a limitation of referring to pheromone as chemical messengers in humans?
Not widely accepted as a process that happens in humans
