Circadian Rythm

Question 1

What is a Circadiam rhythm and give examples

Answer 1

-It is a biological rhythm that lasts for 24 hours.

• Sleep wake cycle
• Body temperature

Question 2

Describe how the sleep wake cycle is reset

Answer 2

-Light will enter the eye, the optical nerve will then transmit a signal to the suprachiasmatic nuclei in the hypothalamus. The suprachiasmatic nuclei will then increase body temperature, blood pressure and suppress the release of melatonin from the pineal gland.

Question 3

Describe how the suprachiasmatic nuclei regulates activity in the sleep wake cycle

Answer 3

• CLK proteins are produced which signals us to wake up and gather around the SCN through out the day to keep us awake.
• High levels of CLK proteins that have been gathered produce PER proteins.
• PER proteins that have been produce will reach high levels and start to shut down CLK proteins therefore we will fall asleep at night as there are low levels of CLK proteins which wont signal our bodies to stay awake.
• Low levels of CLK proteins stop producing PER proteins therefore levels of PER proteins will be reduced and allow CLK proteins to start being produced and gather in the SCN which will signal us to wake up again.

Question 4

What are the peak, moderate and low periods throughout the day for melatonin production?

Answer 4

Peak=2-4 am
Moderate=9 pm
Low-8 am

Question 5

Describe the Circadiam rhythm body temperature

Answer 5

• Body temperature is another Circadiam rhythm
• It is at its lowest in the early hours of the morning before we wake up and highest at the late hours of the early evening before we got to sleep.
• Sleep typically occurs when core body temperature starts to drop and it starts to rise when we are about to wake up to promote a feeling of alertness.

Question 6

What are exogenous zeitgebers for Sleep wake cycle

Answer 6

• levels of day light

Question 7

What are endogenous pacemakers in the Sleep wake cycle?

Answer 7

• CLK and PER proteins
• Suprachiasmatic nuclei
• melatonin

Question 8

Identify AO3 paragraphs for Sleep wake cycle

Answer 8

• Siffre
• Practical application
• Decoursey
• Aschoff and Webber

Question 9

Outline Siffre’s Aim, Method, Findings and conclusion

Answer 9

Aim: to investigate the effect day light had on the sleep wake cycle

Method: Siffre deprived himself from exogenous zeitgebers such as sunlight and natural sound by going into a cave for two months and recoding his sleep wake cycle by attaching electrodes onto his scalp.

Finings: His sleep wake cycle only increased up to 25 hours instead of 24 and he continued to fall asleep and wake up on a regular schedule.

Conclusion: Endogenous pacemakers are more important at regulating our circadian ryhtms as the sleep wake cycle only increased up to 25 hours when there was a lack of exogenous zeitgebers.

Question 10

Outline Aschoff and Webbers Aim, method, findings and conclusion

Answer 10

Aim: To investigate the effect exogenous zeitgebers had on the sleep wake cycle.

Method: They studied participants who lived in a bunker who had no windows and artificial light which participants were free to turn on and off whenever they liked.

Finings: They found that participants sleep wake cycle would increase up to 27 hours

Conclusion: They concluded that the sleep wake cycle does depend on the Exogenous zeitgebers and daylight to be reset and to regulate the activity within the circadian rythm as a result of the sleep wake cycle increasing by three hours.

Question 11

Outline Decoursey’s aim, method, findings and conclusion

Answer 11

Aim: to investigate the effect endogenous pacemakers had on the sleep wake cycle of chipmunks

Method: Decoursey damaged the SCN of 20 chipmunks in an operation and released them into the wild for thirty days and observed them.

Finings: The chipmunks sleep wake cycle completely disappeared and the were all eaten by predators as a result of sleep deprivation.

Question 12

Outline how research into circadiam rythms has had positive real life application

Answer 12

• Evidence from studies on circadian rhythms show us when biological rhythms are disrupted this can cause negative consequences to occur.
• This is shown through people having reduced concentration and focus when they are working night shifts up to 6 in the morning.
• Therefore this has made governments put safety measures in place to make people more productive and safe therefore reducing the expenses that may need to be paid and also having a positive impact on the economy.