Mrs Turner - Circadian Rhythms

Question 1

Circadian rhythms

Answer 1

Biological cycles lasting about 24 hours, optimizing physiology and behavior.

Question 1

Biological rhythms

Answer 1

Cyclical changes in biological systems due to cyclic environmental changes.

Question 2

Circa

Answer 2

Latin for ‘about’, used in the term ‘circadian’ to denote a 24-hour cycle.

Question 3

Free-running circadian rhythm

Answer 3

Biological rhythm unaffected by external cues, like light or clocks.

Question 4

Suprachiasmatic nuclei (SCN)

Answer 4

Master circadian pacemaker in the hypothalamus, synchronizing body clocks.

Question 5

Photoentrainment

Answer 5

Process of setting the body clock to the correct time using light as the primary input.

Question 6

Sleep-wake cycle

Answer 6

Circadian rhythm dictating when to sleep and when to be awake, influenced by light and darkness.

Question 7

Post-lunch dip

Answer 7

Circadian dip in sleepiness occurring between 1-3 pm, influenced by the sleep-wake cycle.

Question 8

Homeostatic control

Answer 8

Regulation of sleep and wakefulness based on the body’s need for sleep and energy usage.

Question 9

Core body temperature

Answer 9

Indicator of circadian rhythm, lowest at about 4:30 am and highest at about 6 pm.

Question 10

Melatonin

Answer 10

Hormone following a circadian rhythm, promoting sleep when produced in darkness.

Question 11

Buhr et al. (2010)

Answer 11

Researchers suggesting that temperature, not light, controls the body clock and circadian rhythms.

Question 12

CASE STUDY
1) Free-Running Circadian Rhythm?
2) Michel Siffre?
3) Siffre’s Studies?
4) Southern Alps Stay?
5) Texas Cave Stay
6) 1999 Underground Stay
7) Aging Effects on Circadian Rhythms

Answer 12

1) Internal body clock without external cues
2) French cave explorer who studied circadian rhythms by living underground
3) Series of experiments living underground without external cues
4) First underground stay of 61 days, resurfaced believing the wrong date
5) Six-month stay with natural circadian rhythm settling to just over 24 hours
6) Study on aging effects, found body clock ticking more slowly
7) Body clock stretching circadian rhythms to 48 hours as age increased

Question 14

Photo entrainment

Answer 14

Process of setting the body clock to the correct time through inputting light which is coordinated by the SCN.

Question 15

What influenced our sleep wake cycles

Answer 15

progesterone and melatonin

Question 16

progesterone
And an example
where does it increase?

Answer 16

this hormone increases in preparation for a possible embryo implantation.
- for example if a women’s egg is fertilised progesterone will increase
- it increases in the uterus

Question 17

Cons & Rods

Answer 17

The presence of light is detected by the cones in the eye which influences the SCN which is the master circadian pacemaker.
When light is detected the cones interact with the SCN to regulate the sleep cycle