Biological Rythms

Question 1

Most animals can measure time

Answer 1

Bio clocks found in every eukaryotic organism tested

Rhythmical nature makes sense with evolution

Question 2

Anticipation of environmental change

Answer 2

Why bio rhythms?
Anticipate environmental change: fruit flies
Synchronize behavior with other events: bees
Measure time: honeybee

Question 3

Endocrine function

Answer 3

Shows rhythmic variation over time

Question 4

Circadian rhythm

Answer 4

About a day, 24 hours
Body temp
Sleep/wake

Question 5

Ultradian

Answer 5

Shorter than day
Sleep cycle
Hunger
Attention span

Question 6

Infradian

Answer 6

Longer than a day
Menstrual cycle
Hibernation
Migration

Question 7

Circannual

Answer 7

Yearly
Hibernation 
Migration
Some reproduction
Garden warbler

Question 8

Biological rhythms can be

Answer 8

Internal: controlled by bio clock
External: external stimuli sync internal cycles

Question 9

Zeitgeber

Answer 9

Time giver, exogenous stimuli

Question 10

Entrainment

Answer 10

Sync with periodic cue in environment

Question 11

Jean Jacques Dortous De Mairan

Answer 11

Identified internal bio clock

Found in plants

Question 12

Organization of circadian rhythms

Answer 12

Single cells, no need for complex nervous system

No single clock, fruit flies have multiple

Question 13

Master clock

Answer 13

Entrained by light dark cycle
Controls all clocks
Photoreceptors control time
Retina hypothalamic tract (RHT)

Question 14

Where is master clock

Answer 14

SCN suprachiasmatic nucleus
Independent
Spontaneous
Self sustaining
Found directly above optic chiasm

Question 15

3 main components

Answer 15

Photoreceptors
SCN
Clock controlled genes

Question 16

Genetic basis of circadian cycle

Answer 16

Self regulated feedback loop
Clock and BMAL1 bind together and enter nucleus
Turn on activity of period and crypto chrome genes
Bind with tau to form complex
Suppresses clock and BMAL1 
Results in less per and cry 
Tau complex declines
Turns on again

Question 17

Central oscillator

Answer 17

Controls bio rhythms

Reset by external light signal

Question 18

Peripheral oscillator

Answer 18

Slave
Regulate local rhythms
Reset by feeding

Question 19

Signals from SCN

Answer 19

Preoptic nucleus to hypothalamus: rhythm of ovulation
Paraventricular nucleus in hypo: neuron endocrine plus autonomic
Leads to pineal which produced melatonin
Can be hormonal: melatonin and glucocorticoids

Question 20

Hormones entrain peripheral oscillators

Answer 20

Melatonin: body temp Rhythm
Glucocorticoids: steroid hormones that control physiology

Question 21

Melatonin

Answer 21

Pineal gland
Connected to eyes
Converted from serotonin 
Sleep and learning
Antioxidant
Protects fetus
Mediated hormones
Helps immune system
Neirodegenerative diseases
Helps set sleep rhythms
Could help with depression

Question 22

Leptin/ghrelin

Answer 22

Decreased appetite, increased appetite

Question 23

Chronobiology

Answer 23

Scientific study of biological clocks and associated rhythms

A biological rhythm is any cyclic change in level of bodily chemical or function