Chapter 13 Midterm 3 Flashcards
What is the origins of biological rhythms?
The earth has a tilt- results in seasons
the earth has a rotation- causes days and nights
What are biorhythms?
inherent timing mechanisms that controls and starts various biological processes
What are biorythims linked to?
the origins of biological rhyms the days and seasons cycles
How are animals regulated by biorhytms? What do they do in response to biorhytms?
animals will migrate to the artic in summer for more food production
Are animals near the poles or near the equatorial regions more effected by seasonal chnages?
Near the poles, sun stays constant in equatorial regions
What are two kinds of biorhytms?
circadian biorhythms and circannual biorhythms
What biorhyms are humans dominated by?
the circadian rhythm of daylight and night
What does the biorhythm of daylight effect?
Pulse rate, blood
pressure, body
temperature, rate of cell
division, blood cell count,
alertness, urine
composition, metabolic
rate, sexual drive, feeding
behavior, responsiveness
to medications
Does biorhytm just effect animals?
no! effects plants too, leaves move in a continuous sin wave according to time
Why do we have color vision?
to see everything in the day
When are we most alert?
at 10 am
What is an ultradian biological rhythm?
less than a day
What is an infradian biological rhythm?
more than a day, ex periods
How do we know rats are nocturnal?
even when there was no light stimulation, the rat is still running at night hours
What is our background as mammals? What is our background as apes? How do they conflict?
We are noctural, apes diurnal so we’re diurnal
When do we have deepest sleep?
at 2 am
When do we have the lowest body temp?
4:30 am
When do we have the highest blood pressure increase?
at 6:30 am
When does the distribution of melatonin stop?
at 7:30 am
When do we have best coordination?
at 2:30 pm
When do we have fastets reactiont ime?
3:30
When do we have most efficient muscles?
at 5
When do we have highest blood pressure?
6:30 pm
When do we have highets body temp?
at 7
When does the distribution of melatonin start?
at 9 pm
Why is looking at phone bad at night?
blue light
What experiment proved that there’s free running rhythms?
Birds were put in constant darkness , and their free running period became more than 24 hours, but in constant light they have the cycle a little less than 24 hours
Are rhytms endogenous?
yes
Why do animals migrate as the days get shorter and longer?
because they anticipate that winter is coming or summer is coming, their internal biological clock signifies it
How does our biological clock make predictions about tomorrow?
can tell us what time to wake up before alarm goes off, around what time we’ll be hungry etc
What does the biological clock regulate?
regulates feeding
times, sleeping times,
and metabolic
activity.
Biological clock
regulates gene
expression in every
cell in the body.
Why does the wildebeast migrate?
their driven by rains, migrate to place where rains happen for fresher grass
What is a zeitgeber?
Is an environmental event that sets biological rhythms, ex: light, tells us its wakey time
What is entrainment?
Determines or modifies the period of a biorhythm
An entrained biological clock allows an animal to synchronize its daily
activity across these seasonal changes, social cues in our species are a part of this
What is seasonal affective disorder?
Exposure to artificial lighting disrupts circadian rhythms and accounts for
much inconsistent behavior associated with accidents, daytime fatigue,
alterations in emotional states, obesity, diabetes, and other disorders.
What is jet lag?
fatigue and disorientation
resulting from rapid travel
through time zones and
exposure to a changed light–
dark cycle
Who has more difficulty adjusting a west to east traveler or a east to west traveler? Why?
west to east travel generally has a more difficult adjustment, because you lose more hours, so you need more days to recover from jet lag
What is persistent asynchronous rhytms? What is it generated by?
Associated with altered sleep
and temperature rhythms,
fatigue, and stress—and even
reduced success by sports
teams, generated by jet lag
What happens if the SCN (suprachiasmtic nucleus) is damaged?
If the SCN is damaged, daily
activities occur haphazardly
What does SCN cells do?
increase metabolic activity during light period
Is the SCN part of the hypothalmus?
Yes
What is the SCN responsible for?
for rhymths
What do SCN neurons maintain?
rhythmic
activity in absence of input and
output
If you take SCN cells and put them in a dish what they retain?
periodic rhytms (24 hr cycle)
What kind of rythms do hamsters have?
precise rhythms
hamsters show what is not learned?
the endogenous rhythm
What happens after lesions to the SCN in hamsters?
hamsters eat
and sleep a normal amount, but the
rhythmic nature of these behaviors
disappears- so they sleep same amount but at different times in cycle
What happens if SCN cells from embryo were put into hamsters with damaged SCN cells?
they will reestablish circadian rhythms.
Hamsters: the
“Swiss” watch of
the circadian
rhythm world
What cells respond to blue light in the retinohypothalamic tract?
ganglion cells
What information does the retinohypothalamic tract carry?
information about light chnages to core cells in the SCN
What SCN divided into?
core and shell
What does the signal from the SCN neurons connect to?
shell nuerons
After the shell neurons are entrained what happens?
The SCN drives slave oscillators and recieves signals from other brain and body areas
What is the SCNS circadian rhytm entrained by?
morning and
evening light
What other things can also entrain or disrupt the SCN?
sudden changes in
lighting, by arousal, by moving about, and by feeding
What are intergeniculate leaflet and raphe nucleus?
pathways through which nonphotic event influence the SCN rhythms
What two things entrain rhymtms?
non photic and photic
What are the two seperate groups of circadian neurons?
M and E cells
What do M cells do?
control morning activity and need light for entrainment
What do E cells do?
Control evening activity and need darkness for entrainment
What can explain morning versus evening people?
individual differences in genes and activity
How does the circadian rhymts work?
The per protein and crytp protein form a dimer, go back inot nucleus, interact at E box, cause synthesis of per mrna at thhen the dimer degrades which takes a bit more than 24 hrs, then it degrades again
What does the per protein stand for? Cry? E box?
period gene
Cry- cryptochrome gene
e box- enhancer box
What is pacemaking?
The SCN pacemaker once entrained by light drives slave oscilaltors which exhibit different circadian functions
How are the slave oscialltrs driven?
via hormones, proteins, and neurotransmitters
Melatoning comes from where and efects what?
pineal gland
How is hamsters circannual sexual activity controlled?
by the circaddian pacemaker, when fdaylight lengthens gonads increase, when daylight shortens gonads shrink
How much of the genome is under epigenetic control of the circadian rhytm?
As much as 10% of the genome is under the epigenetic control of the circadian
rhythm
Are there rhytms for cognitice behaviour?
yes
as animals age, what happens to their functions timeliness?
gets messed up, impairs daily schedule
Why are we scared of night?
time-of-day effect may account for some of our emotional responses to daily
events independent of the events themselves
so circadian rhytm is part of it
What are the issues with daylight savings time?
Changing time increases in car accidents, heart attacks, workplace injuries and
strokes. It’s even been found that judicial sentences tend to be harsher at this time
Permanent daylight-saving time (PDST). PDST delays the onset of morning light
and our circadian clock depends on morning light to be in proper alignment. Evidence
shows that later relative sunrises/sunsets can contribute to increased rates of cancer,
obesity, diabetes and heart attack
What are the three clocks we have?
circadian clock
sunlight clock
social clock
What is the polygraph used to do?
used to measure the electrical activity of the brain and body
What is an EEG?
Record of brain wave activity
What is an EMG?
Electromyogram (EMG)
– Record of muscle activity
What is EOG?
Electrooculogram (EOG)
– Record of eye movements
What are the only primates that sleep in one go?
humans
What are the EEG rythms and states?
Beta rhytm (waking state)- waves with a fast frequnecy, muscle tone, and eyes move
Alpha rhytm (relaxed state) - larg waves with a slow frequnecy, muscle tone, eyes dont move
Theta rhyyms- eeg waves increase, slow fequency, uscle tone, eyes not moving
Delta rhytms- slow, ahve large eeg waves, associated with loss of consoisness, muscle tone, no eye moevemnt
How many stages of sleeps are there?
4
When does N REM sleep dominate
early in the night
What does R REM sleep dominate?
later in night
When does sleep states change?
occur in roughly 90 minute periods
When is R sleep high, Waking? N sleep?
R sleep is high in infancy, W in high in later ages, N sleep is pretty constant
What happens in N sleep?
decrease in body temperature, increase in growth hormone release
– Dreaming occurs in N-sleep, but dreams are not as vivid as in R-sleep.
* Sleeptalking
* Sleepwalking
* Night terrors
* Talking or grinding teeth
* Flailing, banging an arm, kicking a foot
* Maintaining muscle posture during N-sleep
– Sleep may occur in a variety of postures, including standing up, sitting (as might
occur in a lecture), or in any of several reclining positions.
What atonia?
occurs during R sleep, is when muscle is completely inactive, inhibit motor neurons
What else outside of atonia is in R sleep?
mechanisms that regulate body temperature stop working
What is restless legs syndrome?
Reduces time sleeping
~5% of the population
More common in women
Reducing caffeine intake and taking
benzodiazepines appear to help.
L-Dopa is frequently used as a
treatment.
poor iron
uptake in the substantia nigra and some
are helped with iron supplements.
What are night terrors associated with?
NREM
What is the activation synthesis hypothesis?
asserts that dreams are a simply by-product of brain
activity and have no meanings.
What is the evolutionary hypothesis?
suggests that
dreams help people work out solutions to
threatening problems and events.
What do biological theories of sleep say dreams are?
suggest that it is
an energy-conserving
strategy and serves
other functions, such
as staying safe.
What effects sleep time?
Sleep time is
affected by the
amount of time
required to
obtain food and
by the risk of
predations
What cycle dominates our behaviour in the day? What cycle dominates the behaviour at night?
the basic rest activity cycle
By the NREM and REM sleep cycle
Is there any marked physiological effects if you sleep deprive yourself for upto 18 days?
nope
Does sleep deprivation does lead to decreased cognitive performance?
yes
What is microsleep?
sleep lasting a second, probably have this if your up for a long time
how does caffeine effect sleep?
reduces bloodflow of brain
In R sleep deprivation studies what happens?
you wake em up when they’r ein R sleep, studies show that they go back to R sleep more easily after, subjects that spend more time in R sleep in the first available sleep session.
What reduces R sleep, what teh effects?
Antidepressants reduce the amount of R-sleep; no evidence of adverse
consequences.
– Brainstem damage can result in complete loss of R-sleep without any
apparent ill effects
What studies show that during sleep you reprocess waking activity?
neural replay- you record cells from hippocampus of rats, the non rem sleep after food search shows the same connections during the search for food, so maybe they’re dreaming about food.
Done in people we do replay too (pet scans show that brain activity during a test happens the same in REM sleep).
What is the RAS?
reticular activating
system (RAS) is a region in
the pons characterized by a
mixture of cells and fiber
pathways.
What does electrical stimulation of the RAS do?
Electrical stimulation of
RAS produces waking
EEG while damage to it
produces slow-wave
sleeplike EEG.
What parts of the brain are active when rats are mobile? Do humans need to be mobile for thes eparts to be active?
The cholinergic (basal forebrain) and
serotonergic (median raphe) nuclei are
active when rats are awake and mobile.
This is active when we’re interested
What are two brain structures responsible for REM sleep?
peribrachial area
Medial pontine
How is REM sleep happen?
the peribrachial area intitiates REM
the pontine produces rem related actvies and makes PGO waves
Desynchronized EEG in neocortex is produces by the basal forbreain
then we got loss of muscle tone
and then spinal motor neurons are inhibited
What are the sleep disorders of NREM?
Insomnia (problems falling or staying asleep)
- Narcolepsy (inappropriate falling asleep)
What are the sleep disorders of REM sleep?
Sleep paralysis
(inability to move because of motor neuron inhibition).
-Cataplexy (loss of muscle tone)
-Hypnogogic hallucinations (at the beginning of sleep)
What is sleep apnea?
Sleep apnea (not breathing) is a condition
where the person repeatedly wakes up to
breathe. Sleep apnea results in chronic
sleep deprivation.
What helps sleep apnea?
CPAP
What is narcolepsy and how is it caused?
Slow-wave sleep disorder in which a
person uncontrollably falls asleep at
inappropriate times
– Drugs that stimulate dopamine
transmission are helpful.
- Orexin/Hypocretin Neurons are lost
How do dolphins and whales sleep without drowning?
sleep using one hemisphere at the time
What is the number one cause of sleep problems?
sleep medications
Benzodiazepines reduce REM sleep via drug tolerance, whats this mean?
when you take them for a long time they won’t aid in going to sleep cause the body is used to it
