Circadian Rhythms

Question 1

How long?

Answer 1

24 hours

Question 2

Sleep- wake cycle exogenous zeitgebers

Answer 2

Drowsy at nights and alert in the day shows affect of daylight

Question 3

Sleep-wake cycle endogenous pacemakers

Answer 3

Biological clock with no external stimuli is free-running

Question 4

Sleep-wake cycle

Answer 4

Basic rhythm governes by superchiasmatic nucleus which is just above the optic chiasm which provides info from eyes about light

Question 5

Siffre

Answer 5

Free running case study
- 2 months then 6 months living in cave
- lights on when he work up and off when he slepy
- = s/w cycle was 25 hours which was regular

Question 6

Aschoff and Wever

Answer 6

ppts in bunker for 4 weeks with ni natural light
- all but one (29 hours) have a cycle of 24-25 hours

Question 7

Folkard et al

Answer 7

12 ppts with no natural light for 4 weeks
- unknown to ppts the clock was sped up so only 22 hours passed
- = ppts could not adjust to pace
- = suggests existence and strength of endogenous pacemakers

Question 8

Research conclusions

Aschoff and Wever + Siffre

Answer 8

• we have an internal body clock
• absense of exogenous zeitgebers leads to a s/w cycle longer than 24 hours
• exogenous zeitgebers keep our body clock at 24 hours

Question 9

AO3 + application to medicine

Answer 9

Helps determine best time to administer drugs
- heart attacks common in the early morning so drugs to be taken at night with a slow release

Question 10

AO3 + application to work

Answer 10

Shift work results in a desynchronised circadian rhythm which has adverse cognitive and psychological affects
- shift work increases risk of heart disease times 3
- economic implications = how best to manage shift work

Question 11

AO3 - correlation

Answer 11

adverse effects as a result of shift work could be due to the high divorce rates as spend a lot of time away from family

Question 12

AO3 - case study

Answer 12

ppts may not represent wider population which limits meaningful generalisations