Biological Rhythms - BIOPSYCHOLOGY

Question 1

Biological Rhythms

(Circadian rhythms)

Answer 1

All living organisms have them

Changes in body processes across a time period

Question 2

2 Example of Circadian rhythms

+ describe the less important one

Answer 2

-rhythms lasting 24 hours

-sleep/wake cycle

-Temperature
Highest at 6pm
Helps coordinate heart rate, digestion and hormones
High temperature = improved cognition

Question 3

Endo: Suprachiasmatic nucleus

Answer 3

-Nerve fibres connected to eyes cross over in area called optic chiasm (located in hypothalamus)
-SCN lies just above this and recieves info of light directly from here
- Continues even when our eyes are closed, enabling biological clock to ajust to light patterns when we are asleep

(passes light info onto the pineal gland
(-The pineal gland then increases production of Melatonin (when there is little light) - a chemical that induces sleep))

Question 4

Endo: pineal glans and Melatonin

Answer 4

SCN passes info on day length and light to Pineal gland

During night, pineal gland produces Melatonin

Melatonin makes sleep more ‘inviting’ (induces sleep)

Question 5

Exo: Light

Answer 5

Can reset SCN

Indirectly Inhibits production of Melatonin present

(also indirectly influences hormone secretion and blood circulation)

Question 6

Exo: social cues

Answer 6

Schedules set by parents to entrain babies e.g: eating, sleeping

-babies have random cycles until 16 months old when they are entrained

Question 7

Infradian rhythm

Answer 7

Frequency of less than 1 in 24 hrs

Question 8

The menstrual cycle

Answer 8

Governed by monthly changes hormones.
Cycle refers to first day of woman’s period when wall lining is shed to day before her next period.
Cycle takes around 28 days .

Question 9

Is the Menstrual cycle an endogenous system

Answer 9

Yes, by oestrogen and other hormones. although some psychologist argues that it is effected by exogenous zietgebers such as other women’s cycles (pheromones)

Question 10

Seasonal affective disorder

Answer 10

Depressive disorder. Has seasonal pattern of onset.
Symptoms are persistent low moods

During night, pineal gland secretes Melatonin until daylight shows. During winter there is a lack of light. This is thought to affect the production of seratonin- a chemical linked to depression

Question 11

Ultradian rhythms

Answer 11

Frequency of more than 1 in 24 hrs

Question 12

Sleep cycle

Answer 12

5 distinct stages
-occour within around 90 minutes
-each stage characterised via different levels of brainwave activity measured using an EEG

Question 13

What are the 5 stages of The sleep cycle

Answer 13

1, 2, light sleep
3, 4, deep sleep
5:REM

Question 14

Stages 1 and 2 of sleep cycle

Answer 14

-light sleep, person easily woken
-brainwaves slower and more rhythmic(alpha waves)
Becoming even slower as sleep becomes deeper (Theta waves)

Question 15

Stages 3 and 4 of sleep cycle

Answer 15

-delta waves
-even slower, greater amplitude
-hard to wake someone up

Question 16

Stage 5 of sleep cycle

Answer 16

REM sleep
-body is paralysed
-brain activity speeds up to that of an awake brain
-linked to dreaming

Question 17

Who re-surfaced from a cave in mid-September 1962 believing it to be mid-August?

Answer 17

Michael Siffre

Question 18

Who found that participants living in a WW2 bunker for 4 weeks had a circadian rhythm between 24-25 hours?

Answer 18

Aschoff and Wever

Question 19

Who sped up a clock for a 22 hour day and found participants could not cope with the change?

Answer 19

Folkard et al

Question 20

Who found that they could alter women’s menstrual cycles by rubbing the pheromones of another woman onto their top lip?

Answer 20

Stern + McClintock

Question 21

Who found that they could alter sleep patterns of participants by shining lights on the backs of their knees?

Answer 21

Campbell + Murphy

Question 22

Folkard (1977)

temperature study

aims + procedure

Answer 22

• Was interested in cognitive ability and its association with body temperature - Read children stories at 3pm and 9am

Question 23

Folkard (1977)

temperature study

Findings

Answer 23

Children were much more able to recall and understand information from stories read to them at 3pm

Question 24

Aims of Siffre’s study

Answer 24

to study the effects on Endogenous pacemakers on his 24 hr sleep cycle

Question 25

procedure of Siffre’s study

Answer 25

the effects on his rhythms - In 1962 he spent 2 months in a cave - In 1972 he spent 6 months in a cave

No light

Question 26

Findings + of Siffre’s study

Answer 26

in 1962 he resurfaced after 2 months in a cave believing it to be mid August when it was mid September

He always woke and slept in a regular cycle

Question 27

conclusions of Siffre’s study

Answer 27

Endogenous pacemakers do govern the sleep wake cycle

Question 28

Aschoff + Wever study

procedure

Answer 28

Convinced a group of participants to spend 4 weeks in a WWII bunker deprived of natural light

Question 29

Aschoff + Wever findings

Answer 29

All but one (whose sleep/wake cycle was 29 hours) displayed a circadian rhythm between 24-25 hours rather than 24 hours exactly