biopsychology - infradian and ultradian rhythms

Question 1

what is an infradian rhythm

Answer 1

biological rhythm with a frequency of less than one cycle in 24 hours

Question 2

what are 2 examples of an infradian rhythm

Answer 2

menstrual cycle and seasonal effective disorder

Question 3

what is an ultradian rhythm

Answer 3

biological rhythm with a frequency of more than one cycle in 24 hours

Question 4

what are 2 examples of ultradian rhythms

Answer 4

stages of sleep, blood circulation

Question 5

outline the menstruation cycle ( example of infradian rhythm )

Answer 5

10/16 days before period the hypothalamus sends signals to pituitary gland to release oestrogen. This causes ovary to develop an egg. Progesterone is released to thicken lining of womb for pregnancy. If pregnany does not occur, egg is absorbed and lining of womb is shed, reduction in secretion of oestrogen and progesterone. This begins day 1 of the cycle again. Typical cycle is 28 days

Question 6

what exogenous zeitgebers can effect the menstrual cycle (infradian cycle)

Answer 6

stress, diet, medication

Question 7

what endogenous pacemakers can effect the menstrual cycle

Answer 7

hormones released by pituitary gland

Question 8

The infradian cycle of mensturation is an endogenous system, but can be affected by exogenous factors. Outline the study that demonstrates this

Answer 8

Stern and Mclintock studied 29 women with a history of irregular periods. Gathered samples of pheremones from 9 of the women at different stages in their cycle via a cotton pad placed in armpit.
Pad warn for 8 hours treated with alcohol and frozen, rubbed on the upper lip of other pps.

Question 9

What were the findings of Stern and Mclintock’s study?

Answer 9

68% of women experienced changes to their cycle which brought them closer to the cycle of their ‘odour donor’

Question 10

What conclusions can be drawn from stern and Mclintock’s study?

Answer 10

Endogenous pacemaker (pituitary gland and hormones) became entrained by the exogenous zeitgeber (pheremones from other women). This meant the EZ had shifted the EP to bring production of oestrogen to be in sync with the ‘odour donor’.

Question 11

(stern and mclintock) only 68% of women experienced changes to their cycle - what could be said about the 32% that didn’t

Answer 11

There are individual differences in that some people are more influenced by pheremones than others.

Question 12

what is seasonal affective disorder

Answer 12

depressive disorder which has a seasonal pattern, symptoms such as low mood and lack of activity are triggered during winter months when daylight hours become shorter.

Question 13

what are the possible causes of SAD

Answer 13

accumulative disruption to sleep/wake cycle - prolonged periods of daily darkness

during winter the lack of light means melatonin secretion lasts which has a knock on effect on production of serotonin

Question 14

What did Sanassi find that supports the idea that SAD is caused due to a lack of light

Answer 14

Light boxes improved symptoms for 80% of people suffering, Shows SAD is caused by lack of light for most, but not all.

Question 15

how many stages of sleep are there and how long do they last for

Answer 15

5 stages of sleep that last for 90minutes.

Question 16

outline the 1 and 2 stage of sleep (ultradian rhythm)

Answer 16

Light sleep where person can be easily woken, brain waves are high frequency , short amplitude in stage 1.
In stage 2 alpha waves continue but there are occasional random changes in pattern called sleep spindles.

Question 17

outline what occurs during sleep stage 3 and 4

Answer 17

deep sleep, brain waves are delta waves - low frequency high amplitude. difficult to wake someone, growth hormones are released

Question 18

outline what occurs during sleep stage 5

Answer 18

body is paralysed by the pons, brain produces theta waves and REM occurs. dreams most likely to occur here.

Question 19

what is a limitation of Stern and Mclintock’s research (AO3)

Answer 19

research findings are inconsistent and have low external reliability. could be due to small pps study and lack of control over extreneous variables such as stress, diet exercise.
To be 100% valid should only be exposed to pheromones of women in study, this is impossible as pure isolation is unethical.

Question 20

What was Dement’s contribution to psychology (AO3)

Answer 20

Investigated pps in sleep labsm first researcher to use an EEG to measure sleep.This paved way for all future research investigating sleep, first investigator to validate existance of sleep stages and develop a scientific method for measuring and comparing individuals. Therefore can identify what ‘normal’ sleep is and diagnose people with specific sleep disorders.

Question 21

What did Dement find (AO3)

Answer 21

found pps went through 5 stages of sleep characterised by specific wave activity.

Question 22

Why is investigation into sleep so important (AO3)

Answer 22

knowledge can be used to improve people’s experience of sleep by designing apps and technology that can measure sleep by temp, and suggest when to sleep and when to wake up based on which stage of cycle you are in.

Question 23

What is the benefit of understanding the influence EZ have on infradian rhythms such as SAD

Answer 23

Led to development of light therapy, involves having a light box that a patient will turn on in the morning after waking up, or spend time in front of whilst completing tasks to increase serotonin production by the pineal gland. This compensates for the lack of light in the winter and helps reduce symptoms.