bio rhythms - circadian✅

Question 1

what is a circadian rhythm?

what is an endogenous pacemaker?

what is a exogenous zeitgeber?

Answer 1

• a type of biological rhythm, subject to 24 hr cycle, which regulates body processes such as sleep - wake cycle and internal core temp.
• internal biological clocks (endo = internal)
• external changes in the environment ( exo = external)

Question 2

sleep / wake cycle:

why do we feel tired when it starts to get dark?

what is light classed as?

why have studies been conducted? to answer which questions?

Answer 2

• external stimuli such as light influence our internal body clocks
• an exogenous Zeitgeber
• if we didn’t have lightness and darkness, would our bodies know when to sleep and for how long?

Question 3

siffre’s cave study:

what was siffre and what did he study?

what was he deprived of and what did he have?

when did he re- surface and when did he think it was?

findings?

Answer 3

• self styled cave man who spent several periods underground to see the effects of his own biological rhythms
• deprived of exposure to natural light and sound, but has access to food and drink
• resourced in september but believed it Was mid august
• his ‘free running’ biological rhythm settled down to one that was just behind 24 hrs, although he did continue to fall asleep and wake up on a regular interval

Question 4

folkards study:

who did he study?

what did the researchers do during the study without ppts knowing?

how many ppts adjusting got the new regime? what does this suggest?

Answer 4

• 12 ppl who agreed to live in a cave for 3 weeks … sleeping when the clock said 11:45pm and waking at 7:45am
• they sped up the clocks from 24 hrs to 22hrs
• only one … suggests the existence of a strong free- running CR that c ant be easily overridden by changes to the environment

Question 5

AO3:

✅ strength

❌ 2 weaknesses

Answer 5

✅ practical application for shift work - better understanding, those doing shift work through the night reach a circadian trough in the middle of their shift, where mistakes are most likely to occur (BOIVIN ET AL)
research have found a correlation between poor health and shift workers … 3x more likely to develop heart disease

❌ involves smaller groups of ppl, siffre was just one person. meaning generalisations cant be made to the wider pop. as its not representative

❌ poor control - even though they didn’t have access to natural light, they still had articulated lights, siffre had a lamp when he woke up and kept on till he slept. this was assumed that it has n effect on bio. rhythms but it must have.