Biological Rhythms

Question 0

What does the SCN control?

Answer 0

Urine secretion
Respiration
Heart rate
Sleep/wake cycle 
Body temperature

Question 1

Identify and explain two evaluation points to do with methodology for the role of exogenous pacemakers

Answer 1

Use of animals -
Can’t generalise
Can harm animals so it needs to be justified

Reductionist -
Too oversimplified
Need to look at the interaction between exogenous zeitgebers and endogenous pacemakers.

Question 2

What’s the main exogenous zeitgebers?

Answer 2

Light

Question 3

Are exogenous zeitgebers internal or external?

Answer 3

External

Question 4

What two things did Morgan’s study include?

Answer 4

Took SCN out of hamsters and the circadian rhythm disappears

Took the 20 hour circadian rhythms out of mutant hamster and put them in normal hamsters. The hamsters then displayed the rhythms

…support for SCN being he main endogenous pacemaker

Question 5

Are endogenous pacemakers internal or external?

Answer 5

Internal

Question 5

Explain how the SCN interacts with light

Answer 5

Dark
⬇️
Information about light sent to SCN
⬇️
Transmitted to pineal gland
⬇️
Melatonin increases
⬇️
Induces sleep

Question 7

Who spent 7 months in a underground cave?

Answer 7

Michael Siffre

Question 8

What did Lobban say in reference to Luce and Segal’s research?

Answer 8

We used to hunt for over 24 hours in the summer, making use of the light. Now, social synchronisers such as eating behaviour and social customs has caused 24 hour cycles

Question 9

What’s the main endogenous pacemaker?

Answer 9

SCN Of the hypothalamus

Question 10

How did Michael Siffre’s research support the role of endogenous pacemakers?

Answer 10

Found that with the absence of exogenous zeitgebers his sleep cycle was still free running settling at just over 24 hours

Question 11

What is a biological rhythm?

Answer 11

a pattern in physiological or psychological processes which repeats itself over a specified time period

Question 12

What did Luce and Segal find?

Answer 12

People in the arctic circle sleep around 7 hours a day in the summer even though the sun doesn’t set

Question 13

What is a circadian rhythm?

Answer 13

A rhythm that repeats once every 24 hours e.g sleep/wake cycle, body temperature

Question 14

What’s an infradian rhythm?

Answer 14

Repeats less that once every 24 hours e.g menstrual cycle, SAD

Question 15

What’s an ultradian rhythm?

Answer 15

Repeats more that once every 24 hours e.g. Stages of sleep, attention span

Question 16

Other than the SCN, name another endogenous pacemaker

Answer 16

Hormones e.g melatonin

Question 17

Other than light, name two more exogenous zeitgebers

Answer 17

Mealtimes
Clocks
Noise
Temperature 
Social customs

Question 18

Who studied a blind person?

Answer 18

Miles

Question 19

What’s an IDA for the role of exogenous zeitgebers?

Answer 19

Deterministic

Can’t override exogenous zeitgebers and he environment

However, Born -
When told to wake up earlier than usual, participants were able to. This suggest that’s we have free will over our biological rhythms

Question 20

How did Czeisler support Miles’s findings?

Answer 20

Used artificial dim light to alter circadian rhythms down to 22 hours and up to 28 hours

… Light is the main zeitgeber

Question 21

What did Miles find?

Answer 21

The blind person had a circadian rhythm of 24.9 hours despite being exposed to other exogenous zeitgebers.

Supports the idea that light is the main zeitgeber