biopsychology - infradian n ultradian rhythms. Flashcards
What is meant by infradian rhythms?
A type of biological rhythm which has a duration of over 24 hours, may be weekly, monthly or annually.
What are examples of infradian rhythms?
- female menstrual cycle in humans.
- seasonal affective disorder (SAD).
What is the menstrual cycle governed by?
Monthly changes in hormone levels which regulate ovulation.
How long does the menstrual cycle last?
Approx. 28 days from the first day of period to the day of the next period.
What is the menstrual cycle regulated by?
Hormones (endogenous).
What occurs during the menstrual cycle?
- oestrogen increases to cause the ovary to develop an egg and release it (ovulation).
- progesterone thickens the womb lining which prepares the uterus for pregnancy.
What exogenous factors may affect the menstrual cycle?
- health.
- age.
- physical activity.
What is an example of an infradian rhythm?
The menstrual cycle.
What did stern and mcclintock believe?
The menstrual cycle can be influenced by exogenous factors such as the cycle of other women [synchronization from pheromones]
What was the aim of the stern and mcclintock research?
To investigate whether exogenous factors can influence the menstrual cycle.
What was the **procedure* of the stern and mcclintock research?
- the sample consisted of 29 women who had irregular periods.
- samples of pheromones were taken from women at different stages of their menstrual cycle, via a cotton pad placed in their armpit which were worn for 8 hours.
- the pads were sterilised and rubbed on the upper lip of the other women.
- one day one, pads from the start of the menstrual cycle were applied to all 20 women, on day two they were given the pad from the second day of the cycle and so on.
What was the **finding* of the stern and mcclintock research?
68% of women experienced changes to their cycle which brought them closer to the cycle of their ’odour donor’.
What was the **conclusion* of the stern and mcclintock research?
Exogenous zeitgeber such as the cycle of other women can lead to menstruation synchronisation.
What is meant by seasonal affective disorder (SAD)?
Form of depression.
What is meant by seasonal affective disorder (SAD)?
Form of depression.
When are seasonal affective disorder (SAD) symptoms triggered?
During winter months due to reduced daylight hours.
What is the link between melatonin and seasonal affective disorder (SAD)?
- hypothesised that the hormone melatonin is involved in the onset of SAD.
- melatonin is secreted by the pineal gland until dawn where there is an increase in light.
- lack of light means secretion process happens for longer.
↳ influences the production of serotonin in the brain.
What is meant by ultradian rhythms?
A type of biological rhythm which has a duration of less than 24 hours such as the cycle of sleep stages that occur throughout the night.
How many times are ultradian rhythm cycles repeated?
Every 90-100 minutes throughout the night.
What occurs during stage one of the sleep cycle?
- light sleep so can easily be woken.
- slower brain waves
- muscle activity slows down.
- occasional muscle twitching.
What occurs during stage two of the sleep cycle?
- between 1-7 minute.
- bursts of high frequency waves.
- still aware of sounds and activity around us.
- easily woken.
- breathing and heart rate slows down.
- slight decrease in body temperature.
What occurs during stage three and four of the sleep cycle?
- waves start to slow down and become higher in amplitude and wavelength.
- deep sleep.
- difficult to be woken up.
- rhythmic breathing.
- limited muscle activity.
What occurs during stage five of the sleep cycle?
- fast activity of the eye under the eyelid.
- brain becomes very active.
- dreaming and deep sleep.
- heart rate and blood pressure increases.
- body temperature increases.
- muscles relax.
- breathing is rapid and shallow.
What is stage one of the sleep cycle’s waves called?
Theta.
