Biological Rhythms Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Circadian Rhythm (AO1)

A

A biological rhythm that reoccurs approximately every 24 hours. Eg sleep/wake cycle, core body temperature, hormone production.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Infradian Rhythm (AO1)

A

A biological rhythm that has a duration of over 24 hours, and maybe weekly, monthly or annual eg Human menstrual cycle, hibernation in bears and squirrels.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Ultradian Rhythm (AO1)

A

A biological rhythm that lasts less than 24 hours; eg the cycle of sleep stages that occur throughout the night. Eg. hunger/appetite, 90-minute sleep cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Endogenous pacemaker (AO1)

A

Mechanisms within the body govern then internal biological bodily rhythms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is Suprachiasmatic nuclei (SCN)? (AO1)

A

A pacemaker that lies in the hypothalamus is the main endogenous pacemaker (or Master clock).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Exogenous Zeitgeber (AO1)

A

Environmental factors that help synchronise biological rhythms with the outside world; eg light onset which resets the circadian biological clock in the SCN.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Diurnal (AO1)

A

Circadian rhythm in which the animal is active during the day and quiet or asleep at night

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Nocturnal (AO1)

A

Circadian rhythm in which the animal is active during the night and quiet or asleep during the day.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the three types of biological rhythms? (AO1)

A
  1. Circadian rhythm (every 24hrs)
  2. Infradian rhythm (more than 24hrs)
  3. Ultradian rhythm (under 24hrs)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What role does Light play in the sleep/wake cycle? (AO1)

A

Provides the primary input to this system, acting as the external cue for sleeping or waking. First detected by the eye which sends messages concerning the level of brightness to the SCN.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is homeostasis? (AO1)

A

Refers to an organism’s ability to regulate various physiological processes to keep internal states steady and balanced.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the control systems for homeostasis? (AO1)

A

The endocrine and central nervous systems are the major control systems for regulating.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What part of the brain controls homeostasis? (AO1)

A

The hypothalamus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the role of homeostasis in the sleep-wake cycle? (AO1)

A

Tells the body that there is a need for sleep because of energy consumption. Homeostatic drive for sleep increases throughout the day.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does the pineal gland? (AO1)

A

The pineal gland regulates the production and release of melatonin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a Melatonin (AO1)

A

Secreted by the pineal gland. Production is influenced by the detection of light and dark by the retina of the eye.
- Involved in the regulation of sleep cycles (i.e circadian rhythm).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

When does sleeping occur? (AO1)

A

When the core body temperature starts to drop and the body temperature starts to rise towards the end of a sleep cycle promoting feelings of alertness first thing in the morning.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What type of rhythm is temperature? (AO1)

A

Circadian rhythm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What type of rhythm is hormone production? (AO1)

A

Circadian rhythm

20
Q

What are the processes that occur before sleeping? (AO1)

A

Low light → Optic chiasm → stimulate SCN → stimulate pineal → produces melatonin → Brain activity falls → sleep

21
Q

What internal and external factors work together to control the sleep-wake cycle?

A

External factors - Exogenous zeitgebers

Internal Factors - Endogenous pacemakers

22
Q

Name the internal factors that control the natural rhythms.

A

Endogenous pacemakers

23
Q

Name the external factor that controls natural rhythms.

A

Exodogenous zeitgebers

24
Q

What is the sleep-wake cycle?

A

The sleep-wake cycle is an example of the circadian rhythm that is controlled by endogenous pacemakers and exogenous zeitgebers.

25
Q

What is the endogenous pacemaker for sleep?

A

The suprachiasmatic nucleus (SCN) (Part of the hypothalamus). Signals the pineal gland to produce melatonin

26
Q

What is an example of an exogenous zeitgeber for sleep?

A

Light. Light levels signal the SCN to control levels of melatonin production

27
Q

Melatonin production

A

If there is less light more melatonin produced, if there is more light less melatonin is produced.

28
Q

Sleep-wake cycle (AO1)

A
  • An example of a circadian rhythm as it last approx 24hrs
  • Light (detected by the eye) provides the primary input to this system, acting as the external cue for sleeping or waking.
29
Q

What other factor are determined by sleeping and wakefulness?

A

Homeostasis. It tells the body that there is a need for sleep because of energy consumption. This homeostatic drive for sleep increases throughout the day reaching its maximum throughout the late evening.

30
Q

Who is Micheal Siffre?

A
  • Studied his SWC in a cave for 2 months
  • Had no natural light but a lamp
  • Even though he didn’t have the environment telling him when it was the day his SWC didn’t change much. (As SCN determined when to wake. Internal factors)
  • Extended about 25hr
31
Q

What does Micheal Siffre’s research indicate?

A

That the SWC can be maintained with the body’s internal biological clock

32
Q

Siffre (1975) (AO3) Support

A
  • Found that the absence of external cues significantly altered his circadian rhythm.

When he returned from an underground stay with no clocks or light, he believed the date to be a month earlier than it was.

33
Q

What does Siffre (1975)’s research suggest?

A

That his 24hr SWC was increased by the lack of external cues, making him believe one day was longer than it was, leading him to think fewer days had passed.

34
Q

Aschoff & Wever (1976) (AO1) (Supporting Siffres original findings)

A
  • P’s spent 4 weeks in a WWII bunker without natural light
  • 1 Participant SWC extended to 29 hours however everyone reminded between 24-25 hours. (Suggests that the SN is the biological factor that dictates your cycle)
35
Q

What does Aschoff& Wever’s study suggest? (Link)

A

This suggests that the natural sleep-wake cycle may be slightly longer than 24hrs which makes sense as the length of the day is not exactly 24hrs - depending on the time of year.

36
Q

Artificial light (AO3) A-A* application to real-world

A

Research shows that artificial light (Especially SW blue light from the screen can keep people awake)

37
Q

Czeisler et al (1999) (Artificial light) (AO3)

A

Found that they could adjust p’s circadian rhythm using dim lighting.

38
Q

Why would the use of artificial light be a limitation of these studies?

A

Social cues would enable people to copy each other.

39
Q

Practical application to work (AO3) (A-A*)

REAL-WORLD APPLICATION

A

Research on the sleep-wake cycle has informed people about the negative impacts of shift work, especially night shifts eg reduced concentration at night, HD due to disrupted sleep patterns.

40
Q

Practical application to drug treatment (AO3) (A-A*)

REAL-WORLD APPLICATION

A

The pharmaceutical industry can use knowledge of circadian rhythms to decide when the best times for drug absorption is i.e. when digestion is best or when the drug is likely to be the most effective.

41
Q

Limitation of research into the sleep-wake cycle (AO3)

1,

A

Research has shown that SWC typically uses small sample sizes which may not be representative of the wider population which is an issue of generalizability.

42
Q

Individual difference due to point 1. (AO3)

A
  • Not everyone goes to sleep and wakes up at the same time (e.g. early risers, night owls; Duffy et al)
  • Both Siffre and Czeisler’s research showed significant variations in peoples circadian rhythms (between 13 and 65 hours in some cases)
43
Q

AO3 - Individual difference Duffy et al. (2001)

A

Duffy et al. (2001) found that ‘morning people’ prefer to rise and go to be early 9about 6 am and 10 pm) whereas ‘evening people’ prefer to wake and go to bed later (10 am and 1 am)

44
Q

What does Duffy et al. (2001)’s study demonstrate? (AO3)

A

That there may be innate (key factors) individual differences on the circadian rhythms, which suggests that research should focus on these differences during investigations

45
Q

What is free-running?

A

The biological clock that operates in the absence of external cues

46
Q

What is Entrainment?

A

The resetting of the biological clock with exogenous zeitgebers

47
Q

What are the 2 types of Exogenous zeitgebers?

A

Social cues- such as meal times and social activities (Free-running)

Light- Responsible for resetting the body clock each day keeping it on a 24hr cycle (Entrainment)