Biopsychology-Biological rhythms- TB Flashcards

1
Q

What are biological rhythms?

A

Patterns of change in body activity that conforms to a cyclical period

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2
Q

What is a circadian rhythm?

A

A biological rhythm that lasts around 24 hours

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3
Q

What is the main circadian rhythm?

A

Sleep-wake cycle

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4
Q

What drives biological rhythms?

A

Internal body clock

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5
Q

What is the internal body clock that drives biological rhythms?

A

Endogenous pacemaker

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6
Q

What are external changes in the environment that drives biological rhythms?

A

Exogenous zeitgebers

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7
Q

What synchronises circadian rhythms?

A

Master circadian pacemaker= Suprachiasmatic nuclei (SCN) in the hypothalamus

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8
Q

What is photoentrainment?

A

Light providing the main input to the body clock

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9
Q

How does light impact the body clock?

A

Light sensitive cells in eyes detect brightness & send messages to SCN, which uses info to coordinate activity of circadian rhythm (e.g. more awake)

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10
Q

How many points are there when explaining the sleep-wake cycle as a circadian rhythm?

A

6

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11
Q

What is the first point of the sleep-wake cycle?

A

Light & dark= main external signals for sleep/wake

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12
Q

What is the second point of the sleep-wake cycle?

A

Dips and rises in key times- strong sleep = 2-4am & 1-3pm

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13
Q

What is the third point of the sleep-wake cycle?

A

Homeostatic control- tells us to sleep if awake for long

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14
Q

What is the fourth point of the sleep-wake cycle?

A

Circadian system helps keep us awake in daylight but homeostatic=sleepier

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15
Q

What is the fifth point of the sleep-wake cycle?

A

Influenced by daylight too

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16
Q

What is the sixth point of the sleep-wake cycle?

A

If left to own devices & no external cues present, it is “free running” e.g. Michel Siffre

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17
Q

What are two other circadian rhythms?

A

1) Core body temperature- lowest at 4:30am, highest at 6pm, sleep starts as temp drops
2) Hormone production- Pineal gland in brain produces & releases melatonin- peak during dark & encourages sleep

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18
Q

What was the aim of Michel Siffre’s study?

A

To study the influences on circadian rhythms

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19
Q

What was Michel Siffre’s procedure?

A

2nd study- lived in a cave (no light) for 6 month, so that the only thing influencing him was his internal body clock

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20
Q

What were Michel Siffre’s findings?

A

His natural circadian rhythm was 48 hours when young, and just over 24 hours when older (66) but with dramatic variations

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21
Q

What does the homeostatic drive do?

A

Causes increase in need for sleep, throughout the day

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22
Q

When is sleep drive strongest?

A

Between 2-4am and between 1-3pm

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23
Q

What is melatonin?

A

Produced by the pineal gland in the brain in response to darkness (sleepier)

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24
Q

How long are ‘free running’ circadian rhythms?

A

24-25 hrs

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25
What do some suggest is the most important factor in circadian rhythms other than light?
Body temperature more important as it sets timings for cells
26
What support is there for the importance of light in circadian rhythms (criticises temp importance)?
Extremes of daylight in polar regions (Antarctica) responsible forvariations in circadian hormone release
27
What is the importance of individual difference in circadian rhythms?
Research supports that they can vary between 13 and 65 ours- innately different on when their circadian rhythms reach their peak too
28
What research challenges circadian rhythms?
Dim artificial light doesn't affect circadian rhythms- early study findings
29
What research challenges the criticism of circadian rhythms?
Zeisler et al (1999) suggested it isn't true, by altering circadian rhythms by 2-4 hrs each way using dim artificial lighting
30
What real world application is there for circadian rhythms?
Chronotherapetics- Understand how timing affects drug treatments, better for patient now
31
What are ultradian rhythms + example?
Biological rhythms that last under 24 hrs e.g. 5 stages of sleep
32
What are infradian rhythms + example?
Biological rhythms that last over 24 hrs e.g. menstrual cycle
33
What research supports the explanations of ultradian/infradian rhythms?
Tucker (2007)- sleep lab experiment. found differences in stages of sleep and ease of sleep so concluded differences must be biological, not environmental
34
What are 2 strengths of Tucker's study as support for ultradian/infradian rhythms?
1) Control over variables- lab study 2) Showed nature of rhythm is biological, not environmental
35
What is a limitation of Tucker's study as support for ultradian/infradian rhythms?
Different environment may alter sleep as it is artificial & individual differences
36
What is the research support for BRAC? (Ericsson 1980)
Studied elite violinists, athletes & musicians and found they practised for 90 mins segments and had naps to recover, which was consistent with Kleitmans BRAC cycle
37
What are endogenous cues?
Internal cues
38
What are exogenous cues?
External cues
39
What is an examples of endogenous cues?
Hormones
40
What is an examples of exogenous cues?
Phermones
41
Why are studies about the menstrual cycle problematic when evaluating infradian rhythms problematic?
Confounding variable- no cause and effeect
42
What is the real world application of research into the area?
Seasonal affective disorder
43
What is an advantage of real world application of research into rhythms?
Treatment for many is now available
44
What is an disadvantage of real world application of research into rhythms?
Treatment can have side affects
45
What are 3 ways that research into ultradian rhythms has improved understanding of age-related changes in sleep?
1) Slow-wave sleep (SWS) 2) Can explain why elderly people are slower/other age related conditions 3) Development of treatment for medical conditions
46
What are endogenous pacemakers?
Internal biological clocks in the brain e.g. SCN
47
What are exogenous zeitgebers?
Environmental events that influence the biological clock e.g. light
48
What does endogenous mean?
Anything whose origins are within the organism
49
What do endogenous pacemakers do?
Allow us to keep pace with changing cycles in the environment
50
What is the suprachiasmatic nucleus and where is it?
Most important endogenous pacemaker, in the hypothalamus
51
What does the SCN do?
Generates the body's circadian rhythm
52
What influences the SCN in setting our body clock?
Light
53
What's the link between the SCN and melotonin?
The SCN regulates the manufacture & secretion of melatonin in the pineal gland
54
What does melatonin do?
Induces sleep by inhibiting the brain mechanisms that promote wakeness
55
What is the link between the SCN & pineal gland to the outside world?
Their activity must be synchronised with the light-dark rhythm of the world outside
56
Explain light as an exogenous zeitgeber
Receptors in SCN sensitive to light changes as light resets internal body clock daily Rods and cones in retina detect light & the protein melanopsin takes signals to SCN
57
Explain social cues as an exogenous zeitgeber
Meal times & social activities Blind people have same circadian rhythm due to social cues
58
What research did Morgan (1995) do?
Research with hamsters & the SCN
59
What was Morgan's aim?
To investigate the importance of the SCN as an endogenous pacemaker
60
What was Morgan's procedure?
Bred a strain of hamsters with abnormal circadian rhythms (20 hrs not 24) Transplanted SCN neurons from abnormal to normal hamsters and transplanted SCN neurons from normal to abnormal too
61
What were Morgan's findings?
Normal hamsters circadian rhythms became abnormal and vice versa for originally abnormal circadian rhythmed hamsters
62
What do Morgan's findings suggest about the role of the SCN?
Confirms their importance in determining the circadian rhythm in animals
63
What further evidence is there for the role of exogenous zietgebers from Burgess et al (2003)
Exposure to bright light before east to west flight decreases time needed to adjust to local time on arrival Suggests light exposure prior to flight allows travellers to arrive with circadian rhythms already partially re-entrained to local time
64
How does the research by Vetter et al (2011) show light as the dominant zeitgeber for the SCN?
Warm artificial light vs light close to daylight (blue light) used, participants kept daily log of sleep Warmer light= sunrise advanced by 42 mins Blue enriched light= no 42 min adjustment- synchronised to office hours