Circadian Rhythmns Flashcards
what are the characteristics of rhythm
period
frequency
amplitude
phase
chronobiology
study of biological clocks and associated rhythms
rhythm period
length of time to complete one cycle of rhythm
rhythm frequency
number of completed cycles/Time
rhythm amlitude
amount of change above and below rhythm average
rhythm phase
point on the rhythm relative to some objective point during the cycle
Circadian Rhythms: when are the cycles?
name behaviors
day/night
behaviors: sex, learning, parenting, aggression, social behaviors
circatidal rhythm
varies with 12.4 hour tide,
behaviors such as burrowing and feeding
Circalunar rhythm
varies with phases of the moon, present in limited species
Circannual rhythm
varies with season
behaviors such as migration and hibernation
Why are biological rhythms necessary
synchronizes animal behavior with environment, allows to preparation for predictable events
also, synchronizes internal physiological and biochemical processes to promote efficient functioning
diurnal
nocturnal
crepuscular
why/how?
day
night
dawn/dusk
underyling differences in physiology
Name two ways rhythms are controlled and describe each
exogenously controlled rhythms are factors outside of the organism such as light
endogenously controlled rhythms are within the organism such as whatever, melatonin
isolation experiments…
determine endogenous vs exogenous rhythm control
heliotropic plant experiment
leaves open in day close at night
persisted when removed from light
free runnings rhythms deviated slightly from baseline 24hr rhythm in absence of cuesq
Zeitgebers!
potent environmental cue such as light
Entrainment
Process of synchronizing biological rhythms to zeitgebers
free running
rhythms not synchronized to environmental cue
need to study graphs and pictures from
chapter about circadian rhythms
Where are physiological oscillators located in:
amphibians
fish, bird, reptile
mammal
eyes of amphibians
pinneal gland of F, B, R
Suprachiasmatic Nucleus of hypothalamus mammals
study SCN transplantation
Know that Petri dish SCN cells continue to demonstrate circadian rhythms
know about SCN transplantation
T/F melatonin is effected by/effects seasonal behavior
T
Where do mammalian pacemaker cells of circadian rhythms exist
SCN
How is light, received by the photoreceptors of eye, transmitted to the SCN
via the RHT, retinohypothalamic tract