Infradian Rhythms Flashcards
What is an infradian rhythm?
Something that happens less frequently, once a month or once a year
What are two infradian rhythms?
- The menstrual cycle
- Seasonal affective disorder (SAD)
What controls the menstrual cycle?
The pituitary gland
How does the menstrual cycle begin?
First day of bleeding stimulated by gradually increasing amount of oestrogen
What happens in the first phase of the menstrual cycle?
Bleeding slows then stops and the lining of the uterus thickens
What happens in the mid-cycle of the menstrual cycle?
A hormone surge leads to release of an egg (ovulation)
What happens after ovulation?
Progesterone prepares the womb for potential pregnancy, if it doesn’t occur within 2 weeks there is a sharp drop in progesterone and estrogen, this causes the uterus to shed its lining
What is the menstrual cycle governed by?
Endogenous factors, in this case the hormones oestrogen and progesterone
What did Russell show?
When women live together they affect each other’s menstrual cycle
How did Russell show this?
See real women were paired up and daily samples of sweat were collected from one woman and rubbed onto the upper lip of the other woman
What did Russell find?
The women’s menstrual cycles became synchronised with their ‘odour donor’
What did Yang and Schank look at?
The occurrence of menstrual cycles in 185 Chinese women living in university accommodation
What did Yang and Schank find?
No evidence beyond chance level that women synchronise their cycles, they suggest that cycle variability will inevitably lead to repeated cycle
What did Reinberg do?
Conducted a longitudinal study of women in a cave for three months, during that time her menstrual cycle shortened to 21 day cycle
What is seasonal affective disorder?
A form of depression where a person becomes depressed during the winter moths and recover in the summer
