15. Biological Rhythms: Infradian And Ultradian Rhythms AO1 Flashcards
What are the three types of biological rhythms?
- Circadian
- Infradian
- Ultradian
Give an example of an infradian rhythm
The menstrual cycle
How long is the human female menstrual cycle?
About 28 days
What might exogenous zeitgebers do?
Synchronise menestral cycle
What did Stern and McClintock study?
29 women with irregular periods
What was Stern and McClintock procedure?
Pheromones were taken from some at different stages of the cycles via a cotton pad under their armpits
These pads were cleaned with alcohol and later rubbed on the upper lips of other participants
What did Stern and McClintock find?
68% of women experienced changes to the cycle which brought them closer to the cycle of their odour donor
What does SAD mean?
Seasonal affective disorder, another infradian rhythm
What is SAD?
A depressive disorder (low mood, lack of activity) with a seasonal pattern
Often called the winter blues because symptoms are triggered during winter months when daylight hours becomes shorter
What kind of infradian rhythm is SAD
Circannual (yearly) cycle
What my SAD be cause by?
The mormone melatonin
What happens during the night?
The pineal gland secretes melatonin until dawn when there is an increase in light
What occur during the winter
The lack of light in the morning means the secretion goes on for longer
What does longer secretion cause
A knock-on-effect of the production of serotonin in the brain
Give an example of an ultradian rhythm
Stages of sleep
Outline the idea that stages of sleep ate an ultradian rhythm
Sleep pattern occurs in 90 minute periods, divided into five stages, each characterised by different level of brainwave activity
How is brain wave activity measured
EEG
How many stages of sello have been identified
5
What are stages 1 & 2 of sleep
Light sleep - person may be easily woken - Brain waves become slower and more rhythmic slowing further as sleep becomes deeper
What are Alpha waves?
Brain waves become slower and more rhythmic
What are Beta waves?
Brain waves slowdown further asleep becomes deeper
What are stages 3 & 4 of sleep
Deep sleep - difficult to rouse someone - slow wave sleep characterised by delta waves
What is stage 5
R.E.M. sleep - fast jerky activity of eyes - body paralysed yet brain actively speed up
What does R.E.M. stand for
Rapid eye movement
What is phototherapy
A lightbox stimulates strong light in the morning and evening
