Sleep Wake Cycle Circadiam Rythms

Question 1

What are endogenous pacemakers?

Answer 1

Internal body clocks that keep biological processes to time

‘Endo’ means inside and ‘genous’ means producing in ancient Greek.

Question 2

What is the meaning of exogenous zeitgebers?

Answer 2

External cues that entrain internal body clocks

‘Exo’ means outside in ancient Greek and ‘zeitgeber’ means time giver in German.

Question 3

What is the role of endogenous pacemakers?

Answer 3

To regulate biological rhythms internally

They help maintain timing for various biological processes.

Question 4

How do exogenous zeitgebers affect body clocks?

Answer 4

They alter body clocks to match the environment

This includes factors like light and temperature.

Question 5

Fill in the blank: Endogenous pacemakers are _______ that keep biological processes to time.

Answer 5

[internal body clocks]

Question 6

Fill in the blank: Exogenous zeitgebers are _______ that entrain internal body clocks.

Answer 6

[external cues]

Question 7

What is the meaning of ‘circadian’?

Answer 7

Circadian comes from the Latin words ‘circa’ meaning about and ‘diem’ meaning day.

Question 8

What is a circadian rhythm?

Answer 8

A circadian rhythm is a biological rhythm that lasts around 24 hours.

Question 9

What processes are regulated by circadian rhythms?

Answer 9

Circadian rhythms regulate sleep and wake cycles, hormone release, body temperature, and blood pressure.

Question 10

What is the sleep-wake cycle?

Answer 10

The sleep-wake cycle is the pattern of sleep and wakefulness that repeats every 24 hours.

Question 11

What is the endogenous pacemaker?

Answer 11

The endogenous pacemaker (EP) is the internal body clock that maintains the circadian rhythm.

Question 12

What are exogenous zeitgebers?

Answer 12

Exogenous zeitgebers (EZ) are external cues like light and social signals that influence the circadian rhythm.

Question 13

What happens during jet lag?

Answer 13

During jet lag, there can be conflicts between the endogenous pacemaker and exogenous zeitgebers.

Question 14

How does the endogenous pacemaker adjust to new time zones?

Answer 14

The endogenous pacemaker can be entrained by exogenous zeitgebers to adapt to a new time zone, which may take several days.

Question 15

What is the Suprachiasmatic Nucleus (SCN)?

Answer 15

The SCN is the endogenous pacemaker for the sleep-wake cycle, also known as the master clock.

Question 16

Where is the SCN located?

Answer 16

The SCN is part of the hypothalamus within the limbic system, located at the optic chiasm.

Question 17

What happens when light is detected by the SCN?

Answer 17

When light is detected, the SCN sends signals to the pineal gland, stopping the production of melatonin.

Question 18

What is the role of melatonin?

Answer 18

Melatonin is a hormone that results in a sleep response.

Question 19

What is the primary exogenous zeitgeber in the sleep-wake cycle?

Answer 19

Light is thought to be the primary exogenous zeitgeber in the sleep-wake cycle.

Question 20

What are some examples of social cues that act as exogenous zeitgebers?

Answer 20

Social cues include when we time our meals, exercise, or when others go to bed.

Question 21

What are environmental cues that can act as exogenous zeitgebers?

Answer 21

Environmental cues like clocks are also thought to act as exogenous zeitgebers.

Question 22

What is the endogenous pacemaker (EP) in relation to the circadian sleep-wake cycle?

Answer 22

The EP is thought to be free running, maintaining a predictable cycle without constant entrainment by exogenous zeitgebers (EZ).

Question 23

What experiment did Siffre conduct in 1975?

Answer 23

Siffre spent 179 days (6 months) in a cave with no natural light or other potential EZs.

Question 24

What was the result of Siffre’s experiment regarding his body clock?

Answer 24

Siffre’s body clock maintained a regular cycle of around 25 hours without EZs.

Question 25

What does Siffre's experiment suggest about the EP for the sleep-wake cycle?

Answer 25

It suggests that the EP is free running but needs entrainment to keep to the 24-hour day-night cycle.

Question 26

What is the practical application of research into circadian rhythms?

Answer 26

It has implications for pharmacokinetics, affecting how drugs are absorbed and distributed.

Question 27

When is aspirin most effective for treating heart attacks?

Answer 27

Aspirin is most effective if taken last thing at night. ## Footnote This timing reduces the risk of heart attack, which is most likely to occur early in the morning.

Question 28

What guidelines have been developed based on circadian rhythms?

Answer 28

Guidelines for the timing and dosing of a range of drugs, including treatments for cancer and epilepsy.

Question 29

What is a limitation of research into circadian rhythms?

Answer 29

Participants may not be representative of the wider population, limiting the ability to generalize findings.

Question 30

What did Siffre observe about his internal clock?

Answer 30

His internal clock ticked much more slowly at age 60 than when he was younger.

Question 31

What issue is present in research studies on circadian rhythms?

Answer 31

There is poor control in research studies, such as the use of artificial lighting.

Question 32

How did Czeisler et al. (1999) affect participants' circadian rhythms?

Answer 32

They adjusted participants' circadian rhythms from 22 to 28 hours using dim lighting. ## Footnote This suggests that artificial light may reset biological clocks.

Question 33

What study did Aschoff and Wever conduct in 1976?

Answer 33

A group of participants spent 4 weeks in a WWII bunker deprived of natural light.

Question 34

What was the circadian rhythm observed in most participants?

Answer 34

All but one of the participants displayed a circadian rhythm of between 24 and 25 hours.

Question 35

What was unique about the anomalous participant's circadian rhythm?

Answer 35

The anomalous participant had their cycle extended to 29 hours.

Question 36

What does the study suggest about natural sleep/wake cycles?

Answer 36

Natural sleep/wake cycles may be longer than 24 hours.

Question 37

What are exogenous zeitgebers?

Answer 37

Exogenous zeitgebers are external cues like the number of daylight hours and typical mealtimes that entrain circadian rhythms.

Question 38

How do exogenous zeitgebers affect human circadian rhythms?

Answer 38

They entrain humans' circadian rhythms to the 24-hour day.

Question 39

What was the purpose of DeCoursey et al. (2000) study?

Answer 39

To observe the effects of destroying SCN connections in chipmunks on their sleep/wake cycle.

Question 40

What happened to the chipmunks after SCN connections were destroyed?

Answer 40

Their sleep/wake cycle disappeared, leading to increased vulnerability to predators.

Question 41

What was the duration of the observation period for the chipmunks?

Answer 41

80 days.

Question 42

What did the study by Ralph et al. (1990) involve?

Answer 42

Creating 'mutant' hamsters with a 20-hour sleep/wake cycle.

Question 43

What was done with the SCN cells from mutant hamsters?

Answer 43

They were transplanted into normal hamsters.

Question 44

What was the result of the SCN cell transplantation in normal hamsters?

Answer 44

The normal hamsters ended up on a 20-hour sleep/wake cycle.

Question 45

What does the research indicate about the SCN?

Answer 45

It plays a crucial role in establishing and maintaining the sleep/wake cycle.

Question 46

What resets the SCN and affects hormone secretion and blood circulation?

Answer 46

Light

Question 47

What did Campbell and Murphy (1998) discover about light's effect on sleep/wake cycles?

Answer 47

They found that light could produce a deviation in participants' usual sleep/wake cycles of up to 3 hours.

Question 48

What does the study by Campbell and Murphy (1998) suggest about light?

Answer 48

It suggests that light is a powerful exogenous zeitgeber that influences individuals' brains and bodies.

Question 49

How can light be detected according to Campbell and Murphy (1998)?

Answer 49

Light can be detected by skin receptor sites on the body, even when the same information is not received by the eyes.

Question 50

What was the focus of Shih-Yu Lee et al. (2013) regarding mothers of premature or low birth weight babies?

Answer 50

They reported that these mothers have their sleep disrupted.

Question 51

What was the outcome of the bright light therapy given to mothers in the study by Shih-Yu Lee et al. (2013)?

Answer 51

Women receiving the therapy reported improvement in sleep quality compared to a control group.

Question 52

What does the study by Shih-Yu Lee et al. (2013) demonstrate about exogenous zeitgebers?

Answer 52

It shows the effect on sleep quality that exogenous zeitgebers can have.

Question 53

3 evaluations of the effects of EX and EP

Answer 53

SU- EZ- had led to practical treatment applications. An effective treatment for SEASONAL AFFECTIVE DISODER is phototherapy a light box that stimulates strong light in the morning and evening. Releases 60% of symptoms of suffers. LU- use of animal studies to establish cause and effect. SCN unethical to conduct with humans that psychologist won't know the effect of SCN on the sleep wake cycle on humans. LU- total isolation is unrealistic. Unrealistic view of how system works.