Circadian rhythms

Question 1

The nature of circadian rhythms

Answer 1

Driven by our body clocks

Synchronsied by the SCN

Question 2

Sleep wake cycle

Answer 2

Light and darkness are external factors influencing our sleep.
Strongest sleep drives are between 2-4am and 1-3pm.
Our sleepiness will depend on how rested we are.
It is also determined by homeostatic control - when we have been awake for a long time, out energy is used so our HSC tells us we need to sleep.

Question 3

Core body temperature

Answer 3

At its lowest at 4:30am. Highest at 6pm. Drops before bed and rises just before we wake up.
Small drop between 2-4pm too.

Question 4

Hormone production

Answer 4

Production and release of melatonin from the pineal gland follows a circadian rhythm.
Peak during darkness. Encourages feelings of sleep when dark

Question 5

A03: Research support for the importance of light

Answer 5

Hughes tested the circadian hormone release in the people in polar regions. Extreme daylight = variation in CHR

Question 6

A03: Individual differences

Answer 6

Cycle length from 13-65 hours

Question 7

A03: Temperature may be more important than light

Answer 7

Burh - SCN transports information about light levels into neural messages that set bodys temp. Even a small game in temp can send a powerful signal to our body clocks

Question 8

A03: Chronotherapeutic

Answer 8

Real world application - timing of taking medication can have an impact on treatment success