Circadian Rhythms

Question 1

What are Circadian Rhythms

Answer 1

A type of biological rhythm subject to a 24-hour cycle, regulating a number of bodily processes such as sleep/wake cycle and changes in core body temperature.

Question 2

Effects of Daylight

Answer 2

Exogenous Zeitgeber
Feeling drowsy at night and alert during the day demonstrates the effect of daylight.

Question 3

Michel Siffre

Answer 3

Spent time underground to study his own biological rhythms.
His ‘Free running’ biological rhythm settled down to one just beyond usual 24 hours (Around 25).
Internal body clock can regulate without external cues, but slightly extends.

Question 4

Light/Darkness

Answer 4

Circadian Rhythms dictates when we should be awake, light/darkness are external signals that determine when we need to sleep/wake up.
Strongest sleep drive (two ‘dips’) usually occurs between 2-4 am and 1-3 pm.

Question 5

Homeostasis

Answer 5

Tells us to sleep when we have been awake for a long time because of the amount of energy used up during wakefulness.
Drive for sleep increases gradually throughout the day, reaching its maximum in the late evening.