Biological rhythms

Question 1

Define a biological rhythm

Answer 1

A regular variation in the biological activity of living organisms

Question 2

What is the periodicity of an ultradian rhythm and example?

Answer 2

Less than 24 hours - Heart Break

Question 3

What is the periodicity of an circadian rhythm and example?

Answer 3

24hours - sleep/wake cycle

Question 4

What is the periodicity of an Infradian rhythm and example?

Answer 4

More than 24hours - menstrual cycle

Question 5

Describe the sleep cycle as an Ultradian rhythm

Answer 5

90 minute cycles of Stage 1, NREM2, NREM3, NREM4, REM Sleep

Question 6

Describe the Menstrual cycle as an Infradian rhythm

Answer 6

Oestrogen, progesterone - Hormones cause lining of the womb to become engorged with blood and one egg to be released - egg not fertilised, lining is shed, cycle around 28 days.

Question 7

Describe Biological Circadian Rhythms (BCRs)

Answer 7

Green (1994): mammals possess about 100 different BCR’s e.g. body temperature; release of hormones from the pituitary gland and the sleep wake cycle

Question 8

What is believed to control the influence of Endogenous Pacemakers?

Answer 8

The SCN: Suprachiasmatic Nucleus