Biological Rhythms

Question 1

Exogenous zietgeber

Answer 1

Ques that tell your body things e.g. What time of day it is based on the fact the sun has risen

Question 2

Indigenous zietgeber

Answer 2

E.g. Body clock

Question 3

Siffre’s study

Answer 3

• went in to a cave with no light (exogenous zietgebers) for 6 months.
• his free running biological rhythm was about 25 hours long.
• evaluation…

Question 4

Example of an infradian rhythm

Answer 4

Mensteral cycle.

Question 5

Stages of sleep (ultradian rhythm)

Answer 5

Stage 1 and 2- light sleep stages, brainwave patterns start to become slower and more rhythmic (alpha waves) becoming even slower as sleep gets deeper (theta waves)
Stage 3 and 4- delta waves occur which are slower still, and you’re in a deep sleep that’s hard to awake from.
Stage 5 and REM- body is paralysed, yet brain activity speeds up significantly. Where you dream.

Question 6

What’s the suprachiasmatic nucleus (SCN)

Answer 6

A tiny bundle of nerve cells located in the hypothalamus in each hemisphere of the brain. It’s used to maintain circadian rhythms such as the sleep/wake cycle.

Question 7

Animal studies of the SCN

Answer 7

Patricia DeCoursey (2000)

• they destroyed the SCN in 30 chipmunks who were then returned to their natural habitat for 80 days.
• many were killed as the sleep/wake cycle was off which made the vulnerable to preditors.

Question 8

What’s melotonin for?

Answer 8

It’s a chemical that induces sleep and is inhibited during periods of wakefulness.

Question 9

Outline- all biological rhythms

Answer 9

Ultradian rhythms- more than once every 24 hours
Circadian rhythms- daily rhythms
Infradian rhythms- less than once every day. (Menstrual cycle)