Biopsychology- Biological rhythms

Question 1

What are biological rhythms

Answer 1

Cyclical changes in body activity

Question 2

Circadian rhythms definition

Answer 2

Type of biological rhythm that occurs every 24 hours- set and reset by environmental light

Question 3

Endogenous pacemakers definition

Answer 3

Internal body clocks that regulate many of our biological rhythms

Question 4

Exogenous zeitgebers definition

Answer 4

External cues that may affect our biological rhythms

Question 5

Ultradian rhythms definition

Answer 5

Type of biological rhythm with a duration of over 24 hours

Question 6

Infradian rhythms definition

Answer 6

Type of biological rhythm that lasts less than 24 hours

Question 7

Example of circadian rhythm

Answer 7

Sleep/ wake cycle
Release of hormones
Body temperature

Question 8

How do circadian rhythms stay in tune with the external world

Answer 8

Our internal body clock (endogenous rhythms) and external cues (exogenous zeitgebers) work together

Question 9

What is the name of the endogenous pacemaker that controls the circadian sleep/ wake cycle

Answer 9

Suprachiasmatic nuclei (SCN)

Question 10

How does the sleep wake cycle work - describe it using SCN

Answer 10

• light detected in eye, sends message to SCN
  -SCN coordinates activity of circadian system
  -sends signal to pineal gland to increase melatonin at night
  -melatonin induces sleep
  -SCN makes link btwn light and melatonin

Question 11

What is meant by free-running

Answer 11

Our body clocks are left to their own devices in the absence of cues

Question 12

What are the main exogenous zeitgebers for humans?

Answer 12

Light, diet, temperature

Question 13

Does sleep occur when temperature rises or falls?

Answer 13

Rises- falls when waking up

Question 14

A03- research into circadian rhythms

Answer 14

Siffre
- 6 months in cave (food + drink but lack of light and sound)
-free-running body clock = 25 hours
-sleep schedule was fine with absence of EZ
- so sleep/wake cycle is mainly controlled by EPs but EZs are essential to make 24 hour

Question 15

Counter argument to Siffre

Answer 15

Lack pop validity: 1 guy, unique, found internal body clock ran slower- not generalisable
-idiographic, subjective

-highlights individual differences can affect

Question 16

A03- research into endogenous pacemakers

Answer 16

Ralph- support importance of SCN in circadian rhythms
- SCN of genetically abnormal hamsters with CR of 20 hrs removed and implanted into normal hamsters
-CR shortened to 20 hours
-basic period is determined by SCN cells

Question 17

Counter argument to Ralph

Answer 17

Extrapolation issues - external validity (to humans)
-many differences btwn animals and humans
-humans have more social cues can adapt
-cannot be certain humans would respond in the same way

Question 18

A03- research into exogenous zeitgebers

Answer 18

-office workers
-exposed to blue light or warmer, artificial office light
-activity levels were monitored
-blue lights synchronised to office hours
-warmer light synchronise to natural dawn

-light is powerful

Question 19

A03- practical applications

Answer 19

Knowledge of circadian rhythms- better understanding of consequences of their disruption
-accidents at work most likely to occur at night bc of light- sleep deprivation and concentration
- so should use blue light

REDUCES NEGATIVE CONSEQUENCES ASSOCIATED WITH SHIFT WORK