2. BIOLOGICAL RHYTHMS

Question 1

Role of suprachiasmatic nucleus (SCN)

Answer 1

Involved in controlling sleep wake cycle
Location deep in centre of brain
Acts as internal clock + controls daily rhythms, including sleep, physical activity + hormone levels

Question 2

Role of pineal gland

Answer 2

Involved in sleep wake cycle

Responds to signals from suprachiasmatic nucleus- produces melatonin

Question 3

Rechstaffen + Bergman (1995)

Answer 3

Used procedure known as ‘disk over water method’
Rat placed on a disk that spins, brain monitors suggested they were falling asleep
So they would have to move to avoid falling into the water
Died after sleep deprivation, constant temp + generous food available
Increased food intake, lost body heat

Question 4

Recht et al

Jet lag, aim

Answer 4

Impactof travel across time zones on baseball performance by studying season records

Question 5

Recht et al

Results

Answer 5

Found that travelling from east to west would win 43.8% of away games, but west to east= win rate of 37.1%

Question 6

Explanation of Recht

Answer 6

Phase advance- bringing sleep time forward

Phase delay- putting off sleep= better form (east to west)

Question 7

Czeisler et al
Rotating shift work schedules
Aim

Answer 7

Investigate effects of taking properties of human circadian system into account when designing work schedules

Question 8

Czeisler

Sample

Answer 8

153 Male employees
85 on rotting shift work
63 maintained normal shift pattern (control)

Question 9

Czeisler

Procedure

Answer 9

Initial self reports indicated those on rotating shifts experienced significantly more insomnia than control

Question 10

Czeisler

Second distribution of staff

Answer 10

153:

1. 68 original (phase advance)
2. 85 (phase delay)- 21 day cycle (preferred method) or 7 day cycle

Question 11

Czeisler

Results (9 months following altered schedule)

Answer 11

Workers preferred phase delay
Rated themselves as being healthier
Staff turnover on 21 day= reduced

Question 12

Czeisler

Conclusion

Answer 12

Results of field studies suggest work schedules that rotate by phase delay with extended interval between each rotation most compatible with human circadian timings

Question 13

Strengths of Czeisler

Answer 13

Field exp= increased eco validity
Large sample- 153
Useful applications- phase delay most compatible with human circadian timings

Question 14

Weaknesses of Czeisler

Answer 14

Androcentric (reduces population validity)
Field- reduced control
Lacks reliability- not standardised
DC- info briefing
Ethnocentric- cultural bias (diff sleeping patterns)

Question 15

Phototherapy

Dodsom + Zee

Answer 15

Should be sleeping in mug-lies of 90 mins
Remove blue light
Imagine pleasant scenario
Flying east= fly early, west= late

Question 16

Melatonin supplements

Answer 16

Produced in response to darkness
Supplements used to promote restful sleep
Regulates circadian rhythm (internal clock)