lecture 7 sleep and biological rhythms

what is a biological rhythm?

a cyclic change in behavior that occurs at a regular rate

what is an exogenous rhythm?

rhythm that depends of an external stimulus to persist regularly

what is an endogenous rhythm?

rhythm that depends on internal clock mechanism

what is a high frequency rhythm?

rhythm that occurs in short periods, >30 mins (heartrate)

what is an ultradian rhythm?

rhythm within 30m-24 hours(feeding behavior)

what is a circadian/diurnal rhythm?

rhythm that repeats every 24 hours(sleep cycle, hormone expression)

what is an infradian rhythm?

rhythm that is longer than 24 hours(estrous)

what is an annual rhythm?

rhythm that repeats annually(seasonal breeders, migration)

what is zugunruhe?

anxious behavior when migratory animals are unable to migrate

what are circadian rhythms influenced by? (that diurnal are not)

time giver; entrainment

are circadian rhythms exo or endogenous?

endogenous

what makes up the internal clock mechainism?

suprachiasmatic nucleus

where is the suprachiasmatic nucleus found?

above the optic chiasm

what are diurnal rhythms influenced by?

external cues

what is the circadian rhythm of the sleep/wake cycle?

regular periods of sleep and wake repeating

what is the circadian rhythm of hormone secretion?

peak cortisol early in day; free running

what is the circadian rhythm of body temperature?

afternoon peak, low in morning

how is sleep measured?

as levels of alertness; or via EEG

what are the levels of alertness?

-alert wakefulness

-drowsiness

-quiet sleep

-active sleep(REM sleep)

what does alert wakefulness look like? physically and EEG

eyes open, processing

low voltage, fast activity

what does drowsiness look like? physically and EEG

relaxed upper eyelid, more to arouse

low voltage and high activity or high voltage and slow activity

what does quiet sleep look like? physically and EEG

eyes closed, more to arouse

all high voltage, slow activity

what does active sleep look like? physically and EEG

eyes fully closed

low voltage and fast activity

what percent of the day do dogs sleep?

50%, 20% in REM

what percent of the day do cats sleep?

45-65%, 20% in REM

what percent of the day do cattle sleep?

25%, laying down, rarely lateral

what percent of the day do horses sleep?

20%, stand for majority, recumbency for REM

what percent of the day do pigs sleep?

30%, bouts of REM

what percent of the day do poultry sleep?

depends on light cycle, sleep with head tucked