Circadian rhythms Flashcards

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1
Q

What is a biological rhythm?

A

Distinct patters of change in body activity thst conform to cyclical time periods → are influenced by internal body clock EPS and external changes EZs

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2
Q

What is a circadian rhythm?

A

A type of biological rhythm subjected to a 24- hour cycle which regulates processes such as the sleep/wake cycle

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3
Q

What are circadian rhythms?

A

Circadian rhythms are driven by body clocks found in the cells of the body which are synchronised by the SCN (in the hypothalamus).

  • This rhythm needs to constantly be resort by light to allow bodies to be in synchrony with the outside world
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4
Q

What enables the sleep /wake cycle to be maintained?

A
  • Light and darkness EZs are the external cues that determines when we sleep or awake
  • Our homeostatic system tries to enable homeostasis - also note changes energy dips (EPs)
  • Even in the absence of external cues, the internal circadian clock is 24-25 hrs
  • This means internal and external cues combine to enable us to keep rhythm and adjust to changes
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5
Q

Cycle example - core body temperature

A
  • At its lowest at 36c at 4 am and highest at 6pm 38c → normal circadian rhythm sleep occurs when temperature drops and temp rise in last hours of sleep creating feeling in alertness
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6
Q

Siffre - research into circadiun rhythms procedure

A
  • 1972 French cave explorer spent 6 months in a cave
  • No natural light → electricity though
  • Biological clock allowed to free run
  • Wired up to record bodily functions / telephone to outside world and monitored on a camera
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7
Q
A
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8
Q

Siffre - research into circadiun rhythms Findings

A

Erratic sleep - wake cycle at first - settled to 25 hrs

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9
Q

Siffre - research into circadiun rhythms - conclusions

A

we do have an internal mechanism EP that regulates are sleep / wake cycle but it shifts if we do not have EZ to reset it →
* When the biological clocks are left to free run able to maintain a rhythm on their own.

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10
Q

Strengths - circadian rhythms

A
  • RWA-
    Development of chronotherapeutics - timing of drug therapy

The timing of drug treatment has impact on the treatments success
Drugs can be taken hours before release in order to treatment effectively

  • Practical ability
    From research it has been identified the adverse consequences that can occur as a result of disruption to cycles

Night workers in shift work - experience period of reduced concentration at 6 in the morning

Found link between shift work and poor health - more likely to get cardiovascular issues as stress of sleeping

Have economic implications of how to manage worker productivity

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11
Q

Limitations - circadian rhythm

A
  • Psychologists are critical for use of artificial lights
    These may affect the free-running circadian rhythm by acting as an AZ
    Decreasing the internal validity of the research
  • Individual differences
    Length of cycle can vary - 13-65 hours

Duffy - identified early risers Larks and wake later Hours
Explanation
Larks- Mutation of hPer2 gene -
Larks
Owls - mutation hPer3gene

  • Studies of the sleep/wake cycle involve smaller groups of ppt
    Single case studies
    Lack generalizability ie siffre 60 may have an slow body clock as older
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