Circadian Rhythm^

Question 1

Frequency

Answer 1

frequency of around one every 24h
- core body temp
- sleep/wake cycle
- hormone production

Question 2

Endogenous Pacemakers

Answer 2

body’s internal clock that regulate bio rhythms
- suprachiasmatic nucleus

Question 3

Exogenous Zeitgebers

Answer 3

external factors in envi which reset our bio clocks
- light, social cues

Question 4

Sleep/Wake Cycle

Answer 4

light provides the primary input
- set body clock to correct time
- photoentrainment
Entrainment - process that activates/provides timing cue for a bio rhythm
- influence of external factors on internal

Question 5

Light & Dark (Control)

Answer 5

external (EZ)
SCN sits above the optic chiasm
- provide infor from eye about light
light can reset the SCN

Question 6

Homeostatic Control

Answer 6

internal (EP)
tells the body when it needs sleep
- based on how much energy has been used and how long the body been awake

Question 7

Core Body Temp

Answer 7

best indicator for circadian
lowest at 4am (~36)
highest at 6pm (~38)
sleep occurs when core temp drops and wakes when it rises
dips occur between 2-4pm

Question 8

Hormone Hierarchy

Answer 8

Light or Dark
Optic Chiasm
- picks up if it’s light or dark
Suprachiasmatic Nucleus
- determine what’s interpreted and reaction
Pineal Gland
- releases hormone
Melatonin
- more = more sleep

Question 9

Siffre

Answer 9

cavemen for 2 months
to study effect of his bio rhythm
food, water, not sound or natural light
repeated a decade later for 10 months (same results)
both times his own ‘free running’ bio rhythm settled to one just beyond the usual 24h

Question 10

Aschoff & Wever

Answer 10

participant in bunker for 4 weeks
- no natural light
sleep cycle of between 24-24h
- one extended to 29h
Suggested sleep cycle is longer than 24h
- EZ entrain it to 24h

Question 11

Folkard et al

Answer 11

isolated 12 participant in dark cave for 3 weeks
- no light
- manipulated clocks without their knowledge (22h day)
only one adjusted to clock
- show strength of the CR as a ‘free running’ cycle
- questions the extend to which it can be overridden by EZ

Question 12

Poor Study Control

Answer 12

deprived of natural light
still had artificial

Question 13

Shifting the School Day

Answer 13

research show school should be shifted back a couple of hours
- to fit with teen sleep patterns that correspond with hormonal changes
Doing it will show a better academic/beh outcomes
- decrease caffeine dependency

Question 14

VS Shifting the School Day

Answer 14

reasons for not doing this- disruption for parents/ teachers- limits after school activities- won’t end sleep deprivation
: students more likely to stay up longer and have same issues, just later in the day

Question 15

Shift Work

Answer 15

provides an understanding of why adverse consequences occur when CR are disrupted
Boivin et al
- night shift workers are more likely to make a mistake around 6am
Knutsson
- night shift are x3 more likely to develop heart disease

Question 16

VS Shift Work

Answer 16

most of the research on shift workers is correlational
- there could be other variables that cause these adverse effects

Question 17

Medical Treatment

Answer 17

practical application
- chronotherapeutics
treatments can be administered that corresponds to bio rhythms
Asprin for heart attacks should be taken at night
- attack more likely to occur in the morning
:medication taken effect by then