biopsychology: biological rhythms

Question 1

what is the definition of a circadian rhythm ?

Answer 1

daily rhythms

Question 2

give an example of a circadian rhythm

Answer 2

sleep/wake cycle

Question 3

what is it meant by sleep / wake cycle?

Answer 3

dictates when humans and animals should be asleep and awake

Question 4

what is the definition of an ultradian rhythm? give an example

Answer 4

occurs more frequently than once in 24 hours e.g. stages of sleep (90 minute cycles)

Question 5

what is the definition of an infradian rhythm? give an example

Answer 5

occurs less frequently than 24 hours e.g. menstrual cycle

Question 6

what are endogenous pacemakers?

Answer 6

internal body clocks determining when we sleep and wake up, responds to external cues

Question 7

what are exogenous zeitgebers?

Answer 7

external cues that entrain the sleep/wake cycle e.g. light, social cues and meal times

Question 8

what is it meant by the free running body clock?

Answer 8

sleep/wake cycle without external cues- around 25 hours

Question 9

what is it meant by entrainment?

Answer 9

the process where external cues e.g. light keep the internal body clock in line with the 24 hour clock

Question 10

how long was the free running body clock in Micheal Siffre + Aschoff and Weavers study?

Answer 10

Siffre- series of studies on himself , isolated in cave for up to 6 months
Aschoff and Weaver- ps’ spent weeks in WW2 bunker

both found body clock 25 hour cycle

Question 11

ao3: how do these studies support both endogenous and exogenous factors?

Answer 11

suggests importance of an internal body clock but shows also that external factors play some part in the usual 24 hour sleep/wake cycle

Question 12

ao3: why isn’t the internal body clock 24 hours?

Answer 12

actually 24.9 hours, suggested that 0.9 hour is adaptive because it allows us to stay up longer if needed

Question 13

explain how the SCN and the pineal gland work together as the internal body clock

Answer 13

pineal gland produces melatonin which induces sleep by inhibiting brain mechanisms promoting wakefulness , SCN controls pineal gland

Question 14

which hormone is released from the pineal gland?

Answer 14

melatonin

Question 15

name the process of how light can re-set the internal body clock

Answer 15

can re-set SCN through eyes

Question 16

give 3 examples of exogenous zeitgebers

Answer 16

light, social cues (meal times) and body temperature

Question 17

ao3: how does Campbell and Murphys study support the importance of the internal body clock?

Answer 17

showed shining light on the back pf a knee can shift circadian rhythms , showing cells through body contain proteins which are sensitive to light, and therefore shows importance of light as an EZ and SCN is not the only body clock

Question 18

ao3: how does DeCoursey’s study on chipmunks support the role of exogenous/endogenous factors?

Answer 18

destroyed SCN in brains of 30 chipmunks, sleep/wake cycle disappeared and most eaten by predators suggesting they were asleep when they should’ve been awake, supports role of endogenous pacemakers alone and that EZ have little importance

Question 19

ao2: how can research into exogenous/endogenous factors help train babies to sleep at night?

Answer 19

by using social cues (EZ) such as meal times and light (EP) to entrain their body clock such as keeping light off when feeding at night or having them sleep in a dark room

Question 20

ao2: how could an understanding of the impact of exogenous/endogenous factors be used to overcome jet lag?

Answer 20

adapting to local times for sleeping and eating in order to entrain their body clock

Question 21

ao2: how could an understanding of exogenous/endogenous zeitgeibers on shift work have an implication for the economy?

Answer 21

circadian rhythms through 6am, leads to increased accidents and mistakes. has economic implications as we can only work when we are most alert and sleep when we are least, by adapting to this it may lead to more efficiency in the work force, however no employees will be available for early hours

Question 22

what did Folkard find in his study?

Answer 22

wanted to see if external cues could be used to override internal clock, isolated 12 people for 3 weeks and instructed bed time and wake time, then tampered with clock so gradually only 22 hours had passed instead of 24.
to begin with , pps circadian rhythms were synchronised with the clock but as clock quickened, the rhythms did not

Question 23

ao3: does Folkard’s study support exogenous/endogenous factors? why?

Answer 23

supports role of endogenous pacemakers however the more important external factor is light (exogenous zeitgeber)