biological rhythms circadian rhythms

Question 1

what is a circadian rhythm

Answer 1

biological rhythms that last for a 24 hour cycle

(Regulates body proccesses such as sleep/wake cycle and body temperature)

reset by lvls of light

Question 2

what is the sleep/wake cycle

Answer 2

a circadian rhythm (duration of 24 hours), that is goverened by changes in the environment.

e.g. exogenous zeitgebers (external factor/cue)- light
endogenous pacemakers (internal factor/cue) - SCN

Question 3

describe siffres cave study

Answer 3

siffre stayed in a cave for 2 months deprived of external cues e.g. light - exogenous zeitgebers

When he returned he believed the date to be one month earlier than it was.
His biological rhythmn settled beyond the usual 24 hours to around 25hours.

This sugguests that his 24 hour sleep/wake cycle was increased by a lack of extermal cues, making him think one day was longer than it was.

Question 4

ao3: research support that the sleep/wake cycle lasts 24 hours

Answer 4

folkard et al. made ppts sleep in a dark cave and set ppts sleep and wake times that initially fit a 24 hour day.

Then unknown to ppts he sepd up the clock so the apparant 24 hourday lasted 22 hours.

This had a significant impact on the ppts who failed to adjust to the new regimine.
Therefore this sugguests the circadian rhythm of 24 hours cannont be easily effected by exogenous zeitgebers.

Question 5

ao3: issue with case study evidence

Answer 5

the siffre study was on 1 individual and the folkard study was conducted on a small smaple of ppts

Concequently, its impossible to generalise findings to a wider population as there may be individual differences in the research sample that make ppts respond differntly to their sleep/wake cycle. For example, siffre’s observed that his sleep/wake cycle slowed down since he was younger and found that as a 60 year old his body clock was a 48hour cycle.

Therefore its difficult to generalise results from the study onto everyone as other factors may impact our circadian rhythm other than exogenous zeitgebers and endogenous pacemakers e.g. age and gender.

Question 6

ao3: practical application in shift work

Answer 6

shift work has been found to lead to desynchronization of circadian rhytms and lead to cognitive effect. For example research has shown that shift workers suffer from poor concentration around 6am increasing the liklihood of accidents. Research has also shown that shift workers are 3x likely to get heart diesease.

Therefore research into circadian rhytmns has many economic implications, in terms of how to maintain worker productivity.