Biological rhythms

Question 1

what is a rhythm

Answer 1

a function which oscillates or cycles at a regular frequency
Biological rhythms are the overt, measurable activities generated by some internal oscillator (clock)

Question 2

whagt is chronobiology

Answer 2

a field of science that examines periodic (cyclic) phenomena in living organisms and their adaptation to external (environmental) rhythms

Question 3

what is circadian

Answer 3

a daily rhythmical change in behaviour or in a physiological process

Question 4

what is infradian

Answer 4

an infradian rhythm is a rhythm with a period longer than the period of a circadian rhythm. (i.e. with a frequency less than 1 cycle in 28 hours)
ex: reproductive cycles

Question 5

what is ultradian

Answer 5

refers to rhythms with periods shorter than the period of a circadian rhythm
ex: REM cycles in sleep

Question 6

what is Zeitgeber

Answer 6

any external cue that entrains the internal time keeping system of organs

Question 7

what is the function of a biological rhythm

Answer 7

• enable organisms to live in harmony with the rhythms of nature (eg. day and night or seasons) this is known as external synchronisation
• circadian rhythms also maintain temporal organisation of endogenous processes. this is known as internal synchronisation

Question 8

what is the strongest Zeitgeber for both plants and animals

Answer 8

light
others include temperature, social interactions, pharmacological manipulation and eating/drinking patterns

Question 9

what organs regulate biological clocks

Answer 9

1. Retina
2. suprachiasmatic nucleus
3. pineal gland

Question 10

what are some consequences to the disruption of the circadian rhythm

Answer 10

• poor sleep
• depression
• obesity
• type 2 diabetes
• fatty liver disease
• atherosclerosis
• cardiovascular risk
• life span decrease
• enhanced cellular proliferation