infradian rhythms

Question 1

name one type of infradian rhythm

Answer 1

SAD (seasonal affected disorder)
pregnancy
menstruation

Question 2

why is the menstrual cycle an infradian rhythm

Answer 2

the menstrual cycle is governed by monthly changes in hormone levels which regulate ovulation

this cycle typically lasts 28 days

Question 3

when oestrogen levels rise in the menstrual cycle what does this cause

Answer 3

rising levels of oestrogen causes the ovary to develop an egg and release it (this process is called ovulation)

Question 4

what us the role of progesterone in the menstrual cycle

Answer 4

progesterone makes the womb lining grow thicker so it is ready for the fertilised egg

Question 5

what happens during the process of menstruation

Answer 5

if pregnancy doesn’t occur the egg is absorbed into the body, the womb lining comes away and leaves the body

Question 6

what causes women to sync

Answer 6

pheromones (exogenous zeitgebers)

Question 7

what was the procedure of Stern and Mc Clintock’s study

Answer 7

menstrual cycle is controlled endogenously that it can be influence by exogenous factors

29 women with irregular period had pheromones gathered via a cotton pad on their arm pit

pads were worn for 8 hrs, they were treated with alcohol and frozen then rubbed on the upper lip of other participants

on day 1 pads from start of cycle were applied to all 20 participants
on day 2 they were given pads from 2nd day of cycle

Question 8

what were the findings of Stern and Mc Clintock’s study

Answer 8

68% of women experienced changes to cycle which brought them closer to the cycle of their “pheromone donor”

Question 9

what does SAD stand for

Answer 9

Seasonal Affective Disorder

Question 10

what type of disorder is SAD

Answer 10

SAD is a depressive diagnosed depressive disorder in the DSM-5

Question 11

list 5 symptoms of SAD (Seasonal Affective Disorder)

Answer 11

• persistent low mood
• lack of activity and interest in life
• “winter blues” as symptoms are triggered during the winter months when the number of daylight hours is shorter
• SAD is a particular type of infradian rhythms called circannual rhythms as it is subject to a yearly cycle
• can be circadian as it may be due to a disruption to sleep/wake cycle attributed to prolonged periods of daily darkness in the winter

Question 12

what hormone is impacted in SAD

Answer 12

melatonin

Question 13

during the night what is the role of the pineal gland

Answer 13

the pineal gland secretes melatonin until there is an increase of light at dawn

Question 14

why do people tend to get SAD in winter months in terms of hormones

Answer 14

lack of light during winter means the secretion process continues for longer

this then has a follow on effect to levels of serotonin the brain (which is linked to the onset of depressive symptoms)