Biopsychology - 9) Biological Rhythms: Infradian and Ultradian Rhythms

Question 1

Infradian rhythm

Answer 1

Biological rhythm that takes longer than 24 hours (can be weekly, monthly, annually etc)

Question 2

Example of an infradian rhythm

Answer 2

Female menstrual cycle

Question 3

Menstrual cycle

Answer 3

Time between the first day of a women’s period and the day before her next period

Question 4

Duration of menstrual cycle

Answer 4

Anywhere between 24 and 35 days (generally 28 days)

Question 5

Hormones involved in the menstrual cycle

Answer 5

Oestrogen levels rise causing egg to be released and for ovulation to occur
Progesterone helps womb lining grow thicker, readying body for pregnancy

Question 6

Menstrual flow

Answer 6

If pregnancy doesn’t occur, the egg is absorbed in the body and the womb lining comes away to leave the body

Question 7

Who carried out research into the menstrual cycle?

Answer 7

McClintock and Stern

Question 8

Aim of McClintock and Stern’s research into the menstrual cycle

Answer 8

To investigate whether or not the menstrual cycle can be influenced by exogenous zeitgebers

Question 9

Sample of McClintock and Stern’s research into the menstrual cycle

Answer 9

29 women with history of irregular periods

Question 10

Process of McClintock and Stern’s research into the menstrual cycle

Answer 10

Samples of pheromones (chemicals) gathered from 9 of the women at different stages of menstrual cycle
Day 1 - pads from start of menstrual cycle applied to all 20 women
Day 2 - pads from day 2 applied on all 20 women and so on

Question 11

Findings of McClintock and Stern’s research into the menstrual cycle

Answer 11

68% of the 20 women experienced changes to their cycle as a result of the pheromones

Question 12

Conclusion of McClintock and Stern’s research into the menstrual cycle

Answer 12

Exogenous zeitgebers can impact the female menstrual cycle

Question 13

Examples of an infradian rhythm other than the menstrual cycle

Answer 13

Seasonal Affective Disorder (SAD)

Question 14

What is SAD?

Answer 14

Infradian rhythm related to the seasons
People feel depressive symptoms during winter months

Question 15

What neurotransmitter is involved in SAD?

Answer 15

Melatonin

Question 16

Melatonin’s involvement in SAD

Answer 16

Melatonin is secreted by pineal gland
Longer nights in winter increases this secretion
More melatonin linked to increase in depressive symptoms

Question 17

The role of exogenous zeitgebers in SAD

Answer 17

Patients of SAD waking up to an artificial bright light reported an improvement in their depression symptoms

Question 18

Ultradian rhythm

Answer 18

Biological rhythm that takes less than 24 hours

Question 19

Examples of ultradian rhythm

Answer 19

Stages of sleep

Question 20

How many stages of sleep are there and what are they?

Answer 20

5 stages:
- stages 1 and 2 are non-REM
- stages 3 and 4 are non-REM
- stage 5 is REM

Question 21

How long does each stage of sleep last?

Answer 21

Approximately 90 minutes

Question 22

What is each stage of sleep characterised by?

Answer 22

A different level of brainwave activity which can be monitored using an EEG

Question 23

Stages 1 and 2 of the stages of sleep

Answer 23

Light sleep
Individual woken easily
Brainwave patterns become slower and more rhythmic (alpha waves)
Patterns become even slower as sleep becomes deeper (theta waves)

Question 24

Stages 3 and 4 of the stages of sleep

Answer 24

Deep sleep / slow wave sleep (delta waves)
Difficult to wake someone up during these stages

Question 25

Stage 5 of the stages of sleep

Answer 25

REM sleep
Body is paralysed
Brain activity speeds up significantly to resemble that of awake brain
REM activity during sleep highly correlated with dreaming

Question 26

Who conducted research into the stages of sleep?

Answer 26

Dement and Kleitman

Question 27

Process and Dement and Kleitman’s research into the stages of sleep

Answer 27

Brain activity of 0 participants measured using EEG
Participants weren’t influenced by alcohol or caffeine

Question 28

Results of Dement and Kleitman’s research into the stages of sleep

Answer 28

REM sleep highly correlated to dreaming
When he woke up people during REM stage, they could recall very clearly what they dreamed

Question 29

Non-sleep research into ultradian rhythms

Answer 29

During the day we move from states of alternates into states of fatigue every 90 minutes
The human mind can concentrate for 90 minutes but after this the body runs out of resources