Biological rhythms

Question 1

what is an endogenous pacemaker

Answer 1

internal body clocks that play a main role in controlled biological rhythms

Question 2

what is an exogenous zeitgeber

Answer 2

environmental factors that synchronise biological rhythms with the outside world
e.g light

Question 3

what is a circadian rhythm

Answer 3

a bodily rhythm that lasts 24 hours e.g sleep wake cycle

Question 4

what is an ultradian rhythm

Answer 4

a rhythm that lasts less than 24v hours
e.g sleep pattern

Question 5

what is an infradian rhythm

Answer 5

a rhythm that lasts longer than 24 hours
e.g SAD (season affectiveness disorder)

Question 6

How does the sleep wake cycle work when you’re tired

Answer 6

When no light (exogenous zeitgeber) is perceived by the eyes.
A message is sent to the SCN (endogenous pacemaker) to produce melatonin
The SCN instructs the pineal gland to produce melatonin
When melatonin is produced it makes us feel tired inducing sleep

Question 7

Explain the sleep wake cycle when awake

Answer 7

Light is perceived by the retina within the eye. A message is sent to the SCN so as not to produce melatonin the SCN obstructs the pineal gland not to produce melatonin so we stay awake

Question 8

What are desynchronised rhythms

Answer 8

Cycle is out of sync
E.g Jet lag

Question 9

What are desynchronised rhythms

Answer 9

Cycle is out of sync
E.g Jet lag

Question 10

What are symptoms of desynchronization?

Answer 10

Constant tiredness
Attention worsens
Memory is poor
Agitated

Question 11

Who researched circadian rhythms

(2 separate researchers 2 separate studies)

Answer 11

Siffre

Ralph et al

Question 12

What did Siffre study

Answer 12

The human body clock by spending time in a cave with no external cues (clocks,light etc)

Question 13

What happened during Siffres stays in the caves

Answer 13

He ate, slept, awoke when he felt like it with nothing influencing him apart from his internal body clock

Question 14

What did Siffre find after his first stay in the cave

Answer 14

He resurfaced on September 17th thinking it was August 20th

Question 15

What did Siffre find after his second stay in the cave

Answer 15

His natural circadian rhythm had settled down to just over 24 hours but sometimes changed to 48 hours

He also found his internal body clicked slowly compared to when he was a young man (from the first cave)

Question 16

What animal did Ralph et al mutate for his experiment into circadian rhythms

Answer 16

Hamsters 🐹

Question 17

What did Ralph ET al do to the hamsters in his study into circadian rhythmes

Answer 17

He gave the hamster a SCN that lasts 20 hours

Question 18

What did Ralph find after transplanting the new SCN to the hamster

Answer 18

He going that the hamsters rhythm changed from 24 hours to 20 hours suggesting SCN governs cycle length

Question 19

What is SAD (season affectiveness disorder)

Answer 19

This is where people become depressed in the winter — due to it being dark therefore produce more melatonin leading to less seretonin being produced

Lack of seretonin can cause depression

Question 20

Who researched infradian rhythms

Answer 20

Eastman

Question 21

What was the procedure of Eastmans research into people with SAD

Answer 21

96 p.t with SAD
Randomly assigned to one of three groups
1hr 30 mins of bright light in the morning
1hr 30 mins of bright light in the evening
Morning placebo ‘light’

Question 22

What did Eastman find when researching infradian cycles such as SAD

Answer 22

Those with the morning treatment showed significantly more complete remission of their symptoms

Response to evening light was better than placebo but not same level of significance as morning light

Question 23

How is our sleep pattern an ultaradian rhythm

Answer 23

Our sleep pattern is made up of 5 stages lasting 90-100 minutes

Question 24

What are characteristics of stage 1 and 2 of our sleep cycle

Answer 24

Alpha, theta waves
Slow heart rate
Low temperature

Question 25

What are characteristics of stage 3 and 4 of our sleep cycle

Answer 25

Slow wave sleep with delta waves
Metabolic rate slows
Growth hormone is released
Deep sleep

Question 26

What are characteristics of REM sleep

Answer 26

Shows awake brain traits with the eye and brain being active but body is paralyzed

Question 27

Who researched ultradian rhythms

Answer 27

Dement and Klietman

Question 28

Who researched ultradian rhythms

Answer 28

Dement and Klietman

Question 29

What was the aim of Dement and Klietmans investigation into ultradian rhythms

Answer 29

Investigate the change in brain with the different stages of sleep

Question 30

What was the procedure of Dement and Klietmans research into ultradian rhythms

Answer 30

Monitored 9 adults sleep patterns in a sleep lab — EEG recorded brainwave activity

Question 31

What were the findings of Dement and Klietmans research into ultradian rhythms

Answer 31

REM highly correlated with dreaming

Brain activity varied according to how vivid the dreams were p.t were woken during REM had the most accurate recall

Question 32

What is a limitation of biological rhythms

Answer 32

P: a limitation of circadian rhythms is it’s based on case studies
E: in 1999, Siffre repeated his study and found that his internal body clock was slower therefore different results could be produced by the same person
E: suggesting circadian rhythms may not be representative of the wider population
L: therefore we should show caution when generalizing findings

Question 33

What is a strength of biological rhythms

Answer 33

P: A strength of circadian rhythms is the supporting research
E: for example Ralph et Al’s research using a mutated hamster that had a SCN that lasted 20 hours instead of 24
E: they found its rhythm change suggesting the SCN governs cycle length
L; this is a strength of SCB as a determiner of circadian rhythms may as an explanation for why we sleep