Biological Rhythms: Circadian Rhythms

Question 1

Define biological rhythms:

Answer 1

A change in the body processes or behaviour in response to cyclical changes within the environment

Question 2

How are biological rhythms are regulated and governed:

Answer 2

• Endogenous pacemakers

- Exogenous zeitgebers

Question 3

Define endogenous pacemakers:

Answer 3

The body’s internal body clocks that regulate biological rhythms

Question 4

Define exogenous zeitgebers:

Answer 4

External factors in the environment which reset our biological clocks

Question 5

Define circadian rhythm:

Answer 5

A type of biological rhythm that operates along a 24 hour cycle

Question 6

What is an example of circadian rhythm?

Answer 6

• Sleep/wake cycle

- Core body temperature

Question 7

Describe the Cave Study of Siffre (1962), (1972)

Answer 7

-First for two months where he slept and eat when his body told him to

Question 8

Finding of Siffre (1962):

Answer 8

Had slightly above 24 hour circadian (25h)

Question 9

Method of Aschoff and Rutger (1976):

Answer 9

Participants in a bunker for 4 weeks with no natural light.

Question 10

Findings of Aschoff and Rutger (1976):

Answer 10

-Sleep/wake cycle of between 25 and 27 hours (apart from one which extended to 29 hours).

Question 11

Conclusion of Aschoff and Rutger (1976):

Answer 11

-Endogenous pacemakers control the sleep/wake cycle in the absence of light cues.

Question 12

Method of Folkard et al (1985):

Answer 12

Isolated 12 participants from natural light for 3 weeks (dark cave), manipulating the clocks so that only 22 hours passed a day

Question 13

Conclusion of Folkard et al (1985):

Answer 13

• None of the Ps could adjust conformably to the pace of the clock
• Strength of the circadian rhythm

Question 14

Practical application to shift work:

Answer 14

• Shown to lead to desynchronization of circadian rhythms
• Lead to cognitive and physiological effects
• Lack of concentration as 6am, more safety risks
• Shown to have a higher chance of heart disease
• Economical implications of worker productivity

Question 15

What are the implications of shift workers having lapse in concentration?

Answer 15

To the economics:

• Hard to maintain worker productivity
• More accidents happening in the workplace

Question 16

What is the application of research of circadian rhythms in terms of drugs?

Answer 16

Understanding and impact of wrong circadian rhythm can be treated with drug therapies

Question 17

What are the issues with case studies?

Answer 17

Small sample - impossible to generalise to the whole population -May be other factors effecting circadian rhythms e.g age or gender

Question 18

Why does a lack of methodology make it difficult to generalise?

Answer 18

Internal validity is lacking due to lack of control of confounding/ extraneous variables so unable to be clear of what caused the change in circadian rhythms

Question 19

What was the lack of methodology?

Answer 19

Artificial lighting used