circadian rhythms - biopsychology

Question 1

define biological rhythms

Answer 1

patterns of changes in body activity
conform to cyclical time periods

Question 2

what are biological rhythms influenced by

Answer 2

internal body clocks - endogenous pacemakers
External changes in the environment - exogenous zeitgabers

Question 3

define circadian rhythms

Answer 3

biological rhythms

regulate body processes = sleep/wake cycle and changes in core body temperature.

Question 4

what is an important exogenous zeitgaber

Answer 4

light

Question 5

what is the sleep wake cycle governed by

Answer 5

an endogenous pacemaker : suprachiasmatic nucleus (SCN).

Question 6

what resets the SCN

Answer 6

light

Question 7

what did Siffre demonstrate

Answer 7

free running circadian rhythm of 25 hours

Question 8

what is Siffre’s procedure and findings

Answer 8

spent long periods in dark caves - two months (in 1962) and six months (in the 1970s).

free-running circadian rhythm settled to 25 hours

he did have a regular sleep/wake cycle.

Question 9

who spent four weeks in a World War 2 bunker deprived of light

Answer 9

Aschoff and Weaver

All but one displayed a circadian rhythm of between 24 and 25 hours

Question 10

what dose Aschoff and weaver and siffre’s study show

Answer 10

the ‘natural’ sleep/wake cycle may be slightly longer than 24 hours but is entrained by exogenous zeitgebers associated with our 24-hour day

Question 11

what did folkard study

Answer 11

studied 12 people
dark cave for three weeks
bed = 11.45pm waking = 7.45am.
research gradually speeded up clock - 22 hour days

Only one participant comfortably adjusted to the new regime. This suggests the existence of a strong free-running circadian rhythm