Infradian rhythms

Question 1

What are infradian rhythms?

Answer 1

Type of biological rhythms settles with a frequency of less than one cycle in 24 hours

Question 2

What is an example of infradian rhythm and describe this.

Answer 2

Menstrual cycle
- governed by monthly changes in hormone levels which regulates ovulation
- approximately 28 days
- during each cycle, oestrogen rises

Question 3

What are the hormones involved in menstrual cycle?

Answer 3

Oestrogen- rises during each cycle, causing ovary to develop an egg and release it (ovulation)
Progesterone- Thickens womb lining, readying body for pregnancy

Question 4

What did Stern and McClintock suggest about the menstrual cycle?

Answer 4

Menstrual cycle is an endogenous system but suggested it may also be influenced by exogenous factors

Question 5

What was the aim of Stern and McClintock?

Answer 5

Demonstrate how menstrual cycles may synchronise as a result of influence of female hormones.

Question 6

What did Stern and McClintock do? (PROCEDURE)

Answer 6

• 29 women
• samples of pheromones were gathered from women at different stages of their cycles by putting cotton pads in their armpits
• cotton pads were treated by alcohol and frozen and worn by other women in their upper lip

Question 7

What did Stern and McClintock find?

Answer 7

68% women experienced changes to their cycles and became closer with women that provided the cotton pad

Question 8

What does SAD stand for?

Answer 8

Seasonal affective disorder

Question 9

What is SAD described as?

Answer 9

a depressive disorder in DSM-5

Question 10

What are the symptoms of SAD?

Answer 10

• persistent low mood
• lack of interest

Question 11

When is SAD triggered and why?

Answer 11

during winter months because of prolonged periods of darkness in winter

Question 12

What kind of rhythm can it also be classified with and why?

Answer 12

Circadian rhythm because SAD may also be because of disruption to sleep/wake cycle

Question 13

What gland and hormone is associated with the cause of SAD?

Answer 13

pineal gland
melatonin

Question 14

How is melatonin increased and why is it important at night?

Answer 14

Melatonin increases during night when there is an increase in light

Question 15

What does secretion of melatonin during night result in?

Answer 15

Impact serotonin levels