biological rhythms

Question 1

what’re the 3 different biological rhythms

Answer 1

circadium rhythm (occurs once every 24hr)
infradian rhythm (takes >24hr to complete, more than a day)
ultradian rhythms (<24hr to complete, less than a day)

Question 2

what’re 2 key circadian rhythms

Answer 2

sleep/wake cycle

core body temperature

Question 3

what’s the sleep/wake cycle

Answer 3

melatonin peak - 9pm
melatonin trough - 7:30am

Question 4

what is melatonin

Answer 4

a hormone produced by the brain in response to darkness involving the sleep/wake in circadian cycle rhythm

Question 5

when is the core body temperature cycle

Answer 5

~6pm highest body temperature
~4am lowest body temperature

Question 6

what was Folkard’s study of natural biological rhythms

Answer 6

participants lived in a cage for 3 weeks required to sleep from 11:45pm-7:45am. however the experimenters gradually sped up the clock so that 24hrs passed in 22hrs. the participants were unable to adjust, showing how our endogenous pacemakers are dominant over our exogenous zeitgebers

Question 7

what’re biological rhythms

Answer 7

patterns of changes in body activity that conform to cyclical time periods.

Question 8

what influence biological rhythms

Answer 8

internal body clocks (endogenous pacemakers)

external environmental changes (exogenous zeitgebers)

(can be either or both)

Question 9

what was was Aschoff & Wever’s study

Answer 9

participants spent 4 weeks in a ww1 bunker, deprived of natural light. almost all patients had a circadian rhythm of 24-25 hours. shows how usual free-running circadian rhythm is just over 24hrs long however normal day-to-day life is restricted to 24 hours due to exogenous zeitbegers) eg meal times/daylight

Question 10

what does evidence suggest about core body temperature

Answer 10

the warmer we are (internally) the better our cognitive abilities,

Collard found children who read stories at 3pm had greater recall/comprehension than those who read stories at 9am

Question 11

2 positive evaluations of circadian rhythms

Answer 11

night shift

medical treatments

Question 12

2 negative evaluations of circadian rhythms

Answer 12

individual differences

unrepresentative participants

Question 13

what positive evaluation on circadian rhythms can be seen from night shifts

Answer 13

night shift workers have reduced concentration at ~6am, meaning accidents and mistakes are more likely, also night shift workers are 3x more likely to develop heart disease. therefore, companies can better care for the well-being/productivity of their night shift workers e.g. light/breaks

Question 14

what negative evaluation on circadian rhythms can be seen from unrepresentative participants

Answer 14

participants must agree to prolonged periods of time in caves for circadium rhythm studies, making a small and unrepresentative sample size. this has low generalisability due to participants being of certain demographics ie unemployed, introverted, students, or psychological enthusiasts, making the studies less generalisable

Question 15

what negative evaluation of circadian rhythms can be seen from individual differences

Answer 15

some people have sleep/wake cycle differences from 13-65 hours (larks and owls), with age differences also. as a result the data has low applicability due to the vast number of individual differences amongst the population

Question 16

what positive evaluation of circadian rhythms can be seen from medical treatments

Answer 16

the body’s basic processes eg heart rate change within a 24hr period, leading to “chronotheraputics” - research into how medicines can be administered at the most effective times of day eg if aspirin is taken at night rather than day then it’s more effective as a treatment for heart disease. this is a strength as it has allowed for better/faster recoveries better benefiting society

Question 17

summarise the 5 cyclical processes that occur during a menstrual cycle

Answer 17

•~28 day regularity
•ovulation occurs halfway (14 days)
•ovulation occurs at peak oestrogen levels
•after ovulation, progesterone levels increase to rebuild uterus lining
•processes regulated by the ovaries

Question 18

what was McClintock’s study

Answer 18

took 29 women with irregular periods, 9 of which gave pheromone samples at various stages of the menstrual cycle by wearing a cotton pad in the armpit for 8 hours, later rubbed on the top lips of the 20 women. repeated each day. inspired by the finding that women who spent extended time together in uni halls often synchronised their menstrual cycles

Question 19

what’re the McClintock results

Answer 19

68% experienced cycle changes that brought them closer to their ‘odour donor’

Question 20

what is Seasonal Affective Disorder (SAD)

Answer 20

common infradian rhythm, a kind of depression which seems to occur on a seasonal basis, with ~11,000,000 US sufferers

Question 21

where does SAD most commonly occur

Answer 21

North, eg in Florida (far South) ~1.4% of the population, Maine (far North) has as high as 10%

Question 22

why does SAD thought to occur

Answer 22

in more Northern latitudes there is decreased amounts of daylight in winter, causing melatonin to be secreted for longer periods of time due to the lack of light, thought to have an effect on serotonin and creating depressive symptoms

Question 23

what’re 2 positive evaluations of infradian rhythms

Answer 23

evolutionary basis

practical applications in the form of treatments

Question 24

what’s a negative evaluation for infradian rhythms

Answer 24

many confounding variables in McClintock’s study as many factors effect menstrual cycle eg stressed diet and exercise. therefore difficult to establish cause-and-effect and lowers internal validity. furthermore the sample size of 29 women is small and other similar studies have failed to find evidence of menstrual synchrony in female samples

Question 25

how is evolution a positive evaluation for infradian rhythms

Answer 25

if females have birth at the same time then new-borns could be cared for collectively, increasing survivability chances, for example if a mother dies in pregnancy then the child will still have access to breast milk

Question 26

how is applications of infradian rhythms (SAD) a positive evaluation

Answer 26

new treatments have been developed, eg light therapy with a strong light box that relieves symptoms in ~80% of sufferers of SAD. strong light is said to reset melatonin levels which resets the body’s internal clock. whilst light therapy is light/effective it can cause headaches and eye strain. However, relapse rates have been recorded at 46% with light therapy and only 27% with CBT

Question 27

what’re ultradian rhythms

Answer 27

frequency of more than once every 24 hours, the stages of sleep

Question 28

how long do the 5 distinct sleep stages span altogether

Answer 28

~90 minutes

Question 29

what’re characteristics of the 1st stage of sleep

Answer 29

~5 minutes, change from wake to sleep, follows REM, alpha waves, muscles relax/often twitch

Question 30

what’re characteristics of the 2nd sleep cycle

Answer 30

40-50 minutes, light sleep, breathing/heart rate slow, slight body temp decrease, ~half of your sleep, alpha waves

Question 31

what’re characteristics of the 3rd/4th sleep cycle

Answer 31

15-20 minutes, deep sleep begins to move to very deep sleep, breathing/heart rate slow, limited muscle activity, hard to wake, delta brain waves

Question 32

what’re characteristics of the 5th sleep cycle

Answer 32

REM, brain is very active with theta waves, dreams, heart rate/bloody pressure increase, body/muscles often inactive - maybe ‘sleep paralysis’

Question 33

how do the sleep cycles work

Answer 33

the more sleep cycles completed the less deep sleep needed and more time spent alternating from light and REM sleep

Question 34

what’s a positive evaluation of ultradian rhythms

Answer 34

helps better understand age related sleep changes, SWS (slow wave speed) reduces with age, growth hormone usually produced during SWS, may explain issues eg reduced alertness, relaxation techniques or medication can be prescribed and helps ensure better SWS among elderly

Question 35

what’s a negative evaluation of ultradian rhythms

Answer 35

sleep labs and EEG’s are used, very unrealistic, leads to non-generalisable results with low internal validity