Biological rhythms: Circadian rhythms

Question 1

Biological rhythms

Answer 1

Patterns of changes on body activity that conform to cyclical time periods. They are influenced by internal body clocks (endogenous pacemakers) as well as external changes to the environment (exogenous zeitgebers)

Question 2

Circadian rhythm

Answer 2

A type of biological rhythm subject to 24 hour cycle which regulates a number of body processes such as sleep/wake cycle and body temp.

Question 3

Siffre’s cave study

Answer 3

Spent time in a cave to study the effects on his own biological rhythms. He was derived to natural light and sound but had food and drinks. He resurfaced two months back to land. Decade later he performed same thing again but for 6 months in a Texan cave. In both cases his free running biological rhythm settled down to one that was beyond 24 hours (around 25) though he did continue falling asleep and wake up on a regular schedule.

Question 4

Aschoff and Wever

Answer 4

had a group of ppts who spent 4 weeks in WWII bunker deprived of natural light. All ppts but one displayed a circadian rhythm between 24 and 25 hours . Both Siffre and Aschoff and Wever’s study shows that the exogenous zeitgeber is entrained to our 24 hour day

Question 5

Folkard et al

Answer 5

Studied group of 12 people who agreed to live in dark cave for 3 weeks. They retired to bed when the clock said 11:45pm and rose when it said 7:45am. Researchers then gradually speeded up the clock (ppt no aware) . None of the Pp’s could adjust comfortably
to the pace of the clock, showing the strength of the circadian rhythm as a free-running cycle.