Biological Rhythms and Sleep Flashcards
Biorhythm
Inherent timing mechanisms that controls or initiates various biological processes
Biological clock
-Neural systems that time behavior
-Allows animals to anticipate events before they happen
-Ex: birds migrating before it gets cold
Biological rhythms are ______, their control comes from _______
endogenous, within
Circadian rhythms
functions of a living organism that display a rhythms of about 24 hours
Ultradian rhythms
-periods of less than a day
-ex: activity, feeding, hormone release
Infradian rhythms
-period of more than a day
-ex: body weight, reproductive cycles
Circannual rhythms
-period of about a year
-ex: migratory cycles of birds
Free-running rhythm
-rhythm of the body’s own devising in the absence of all external cues
Without input from external cues, our bodies have their own rhythms with periods of about ____ to ____ hours
25, 27
Sleep-wake cycles shift about ____ or so every day
an hour
Daily fluctuations that bodily processes rely on
-temperature
-Melatonin
-cortisol
Phase advance
-light exposure in the morning
-light avoidance in he middle of the night
Phase delay
-light exposure in the evening
-light avoidance in the morning
Eastward travel requires phase ______ and westward travel requires phase ______
advance, delay
Melatonin therapy
-easiest way to adjust sleep-wake cycle to combat jetlag
-advance: administer melatonin after normal peak
-delay: administer before the normal peak
Suprachiasmatic nucleus (SCN)
-found in hypothalamus
-main circadian pacemaker in the brain
SCN damage in rodents
eating, drinking, exercise, and sleep occur at a normal amount, but at haphazard times
SCN metabolic activity is _____ during the light period of the day-night cycle than it is during the dark period
higher
T/F: If all of the pathways to and from the SCN are cut, rhythmic electrical activity stops
false
There is a pathway directly from the _____ to the SCN
eye
Melanopsin
photopigment that is especially sensitive to blue light
Retinohypothalamic pathway
Pathway that light information travels down from the eye to the SCN
M-cells
type of circadian neurons that control morning activity and need to be trained by light
E-cells
type of circadian neurons that control evening activity and need to be trained by darkness
SCN cells in mammals make two proteins
clock and cycle proteins
what two genes to clock and cycle proteins promote transcription for
period (per) and cryptochrome (cry)
After production period and cryptochrome proteins…
dimerize
T/F: no new clock and cycle proteins are produced until the period and cryptochrome proteins degrade
true
How is light detected in mammals
retinal ganglion cells detect light and release glutamate in the SCN
Glutamate triggers events that promote ____ protein production
period
Tau mutations cause
shorter periods of about 20 hours
Slave oscillators
control the rhythmic occurrence of one bodily function (ex temperature)
controlled by SCN
Basic rest-activity cycle
best known ultradian rhythm
lasts for about 90 minutes
measures arousal levels
EEG
measures brain activity
measures sleep stages
Beta rhythm
waking state
fast brain wave activity (15 to 30 hz)
Alpha rhythm
drowsy state
large, regular brain waves (7 to 11 hz)
Delta rhythm
sleeping state
slow brain wave activity (1 to 3 hz)
associated with deep sleep
REM sleep
Dreaming state
fast brain wave pattern
indistinguishable from beta rhythm EEG
only difference is that muscles are unresponsive
Atonia
absence of muscle tone
T/F: your body still thermoregulates during REM sleep
false
____ in body temperature and ______ in growth hormone release during non REM sleep
decrease, increase
Sleep talking, sleepwalking, and night terrors occur during
NREM sleep
First half of sleep is…
NREM dominant
Second half of sleep is…
REM dominant
At the end of each REM period you…
briefly wake up
A sleep cycle is a period of ____ followed by a period of ______
SWS, REM
When does the circadian rhythm shift making it so people wake up later
Puberty
Dolphins don’t show
REM sleep
How do dolphins and some birds sleep
one hemisphere at a time
Fatal fetal insomnia
-in midlife, people stop sleeping and die 7-24 months after the onset of the insomnia
-autopsy shows brain degeneration
Sleep recovery
process of sleeping more than normal after a period of deprivation
Night 1 of sleep recovery
stage 3 sleep increases, typically at the expense of stage 2 sleep
Night 2 sleep recovery
most recovery of REM sleep that is more intense than normal
Sleep as a passive process
early explanation that sleep is a passive process that takes place as a result of a decrease in sensory stimulation
Sleep is an energy-conserving strategy
-period of reduced muscular tension, heart rate, blood pressure, temp, and respiration
-gather food at optimal times and sleep to conserve energy the rest of the time
-only has a correlation in prey species
Sleep as a restorative process
-replenishes the body via metabolic requirements such as proteins
-most growth hormone is released during SWS
-sleep is suggested to reduce illness
-glia flush waste products faster than when awake
