Circadian Rhythm

Question 1

What is the circadian rhythm?

Answer 1

A biological process that displays an endogenous, entrainable oscillation of 24 hours

Question 2

What’s the diff between endogenous and exogenous?

Answer 2

Endogenous - mediated by internal body clock

Exogenous - mediated by activity-sleep

Question 3

What factors effect the body clock?

Answer 3

Light
Social interaction
Food/drink - Thermic effect
Activity

Question 4

How does the circadian biological clock respond to a stimulus like light?

Answer 4

Light travels to the suprachiasmatic nucleus (group of cells in the hypothalamus that respond to light/dark signals) via the retinohypothalamic tract, signalling to other parts of the brain to: produce cortisol and delay the release of melatonin, raise body temp and other functions that make us feel awake.

Question 5

Why is elevation in melatonin levels beneficial on an evening?

Answer 5

Melatonin is associated with sleep onset and is produced when the eyes signal to the SCN that it is dark. It promotes sleep.