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Biological Rhythms > Test 1 Review > Flashcards

Test 1 Review Flashcards

1
Q

what are biological clocks used for?

A

predict events that occur at regular intervals and anticipate change

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2
Q

what is an example of social adaptation to rhythms?

A

getting up for school/work at the same time every day regardless of changes in sunrise/sunset times in different locations throughout the year

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3
Q

what is a possible explanation for the development of clocks in organisms?

A

escaping from UV rays that damage DNA while still using light for energy

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4
Q

what is the major external synchronizer for marine animals?

A

tides, therefore moon phases

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5
Q

what are examples of a temporal program?

A

gonyaulax float during the day to collect light for photosynthesis, in the evening they sink down into the water column to fix nitrogen where they glow/sparkle; crassaculae (desert plants) separate photosynthesis and carbon fixation processes into day and night so they can safely open stomata without losing water; human hormones fluctuate based on sleep/wake cycle

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6
Q

what human hormones peak during the day and fall at night?

A

VLPO, adenosine, hypocretin

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7
Q

what human hormones peak at night and fall during the day?

A

GH, melatonin

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8
Q

how long is an ultradian rhythm?

A
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9
Q

how long is an infradian rhythm?

A

> 28 hours

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10
Q

what kinds of laboratory results support the idea of physiological clock mechanisms?

A

organisms maintaining rhythmic free running periods during DD laboratory conditions (mouse, hamster), organisms with clock mutations having arrhythmic free running periods

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11
Q

what are examples of biological clocks being used for orientation and/or migration?

A

bees use position of sun to communicate location of food sources to other bees and use internal clock to calculate locations at different hours of the day, amphipods use clocks to escape from predators, migratory birds use sun/stars for navigation, monarch butterflies follow directions of UV light

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12
Q

what are examples of biological clocks being used for reproduction/social behaviour?

A

coral populations all mass reproduce at one time, cashew plants reproduce annually, nocturnal cactus only blooms one night per year

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13
Q

how is sleep regulated? (what kind of clock)

A

seasonal

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14
Q

when does morning/evening preference develop and how does it differ between sexes?

A

puberty, females tend to prefer evening

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15
Q

how is time perceived?

A

an internal clock that anticipates irregular changes while assuming a 24 hour period

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16
Q

who first recorded daily rhythms?

A

Androsthenes

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17
Q

what did de Mairan record?

A

regular opening and closing of mimosa leaves in absence of LD cycle

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18
Q

what did de Candolle record?

A

plants are rhythmic without LD cycles but their rhythms are not exactly 24 hours

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19
Q

what did Linnaeus record?

A

flower clock (GAYYYYYYY)

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20
Q

what did Stoppel record? (fuck her)

A

bean plants daily leaf movement cycle stopped in mine shaft, so factor x must also affect rhythmicity

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21
Q

what did Kalmur record?

A

fruit fly eclosion is rhythmic, metabolism can be stopped and eclosion can be delayed by exposing flies to pure helium environment (delay is amount of time spent in helium)

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22
Q

what did Bunning record?

A

photoperiodism, drosophila become arrhythmic in LL cycle but resume rhythmicity in DD cycle, innateness (temp changes affect eclosion; lower = slower (delays))

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23
Q

what did Frisch record?

A

honey bees remember time of day they encountered food`

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24
Q

what did Kramer record?

A

birds use sun compass orientation (internal clock + sun position) to navigate during migration

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25
Q

what did Pittendrigh record?

A

organisms internal clocks anticipate changes in environment and so are affected by temperature through compensation for temp changes

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26
Q

what did Aschoff record?

A

emotions of humans throughout the day is rhythmic

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27
Q

what is tau?

A

length of endogenous rhythm

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28
Q

what is zeitgeber?

A

external time synchronizer

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29
Q

what is circadian time?

A

inner day/night cycle

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30
Q

what is phase shift?

A

rapid change in oscillation from one phase to another

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31
Q

what is phase angle difference?

A

difference between points from inner cycle and outer cycle

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32
Q

what is Q10=1?

A

rate of reaction changes by one unit with every 10 degree temp change

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33
Q

what is the perch behaviour of sparrows in LD12:12 and DD?

A

begin activity in subjective day CT0, in LD12:12 cycle sparrows synchronize (are diurnal), in DD they shift right (longer than 24 hours)

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34
Q

what is the activity of hamsters in LD12:12?

A

assume winter physiology, reproduce slower, internal rhythm shortened

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35
Q

what is entrainment?

A

when free running period does not equal environment, it is adjusted

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36
Q

what is masking?

A

when social zeitgeber rapidly changes but inner cycle adjusts slowly e.x. jet lag

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37
Q

what are two ways entrainment can occur?

A

change period (tau), reset phase every day

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38
Q

what are Aschoff’s rules?

A
  1. when light intensity increases, tau in nocturnal animals increases, tau in diurnal animals decreases
  2. tau in LL > tau in DD in nocturnal, tau in LL rest in LL in diurnal, rest > activity in LL for nocturnal
  3. tau 24 hours in diurnal
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39
Q

what is the behaviour of mice in LD12:12, DD, LD12:14, and LD12:10?

A

LD12:12 runs in dark i.e. subjective night, DD running length increases tau is close to 24 hours, LD12:14 delays cycle to synchronize, LD12:10 tau is shorter from LD12:14 so mouse now behaves like diurnal animal

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40
Q

what is relative coordination?

A

when periods of inner cycle and zeitgeber are too different for entrainment to occur

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41
Q

what is parametric entrainment?

A

entrainment that involves qualities of light

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42
Q

what is nonparametric entrainment?

A

entrainment based on presence or absence of light, accomplished through daily phase shift

43
Q

what do phase response curves show?

A

relationships of delays or advances caused by pulses of light

44
Q

what are CT0, CT12?

A

CT0 beginning of subjective day, CT12 beginning of subjective night

45
Q

what are the effects of light pulses at CT0-12, CT12-18, CT18-0?

A

CT0-12 no effects, CT12-18 phase delays, CT18-0 phase advances

46
Q

what are the effects of light pulses in the forbidden zone?

A

no entrainment, cycle is just interrupted

47
Q

what is the phase angle difference equation?

A

delta phi = tau - T

48
Q

how can phase angle of entrainment be altered?

A

changing circadian period (light pulses in delay or advance zones), changing zeitgeber period (lab only), changing shape of PRC, changing sensitivity of system to zeitgeber, masking/after effects, phase shifting to nonphotic stimuli

49
Q

what are nonphotic stimuli?

A

everything that is not light changes/pulses, including dark pulses which are not just absence of light, have greatest effects when introduced at unexpected times

50
Q

what is are the effects of triazolam?

A

mimics effects of dark pulses, makes hamsters run like crazy when they have a wheel, no effect on activity when they don’t have a wheel

51
Q

what are the effects of dark pulses?

A

cause phase shifts in subjective day, requires behavioural activation/arousal

52
Q

what are the effects of introduction of a novel running wheel?

A

mimics effects of dark pulses/triazolam

53
Q

how can stimuli interact?

A
  1. shift by one stimulus moves clock such that second stimulus falls at a new CT
  2. in rodents, simultaneous arousal can reduce effects of light induced shift
  3. in rodents, nonphotic shift followed by photic shift negates effects of light pulse
  4. changes in light intensity can cause behavioural arousal
54
Q

what is an example of nonphotic entrainment?

A

insect vector of chagas disease can be entrained using chicken pulse

55
Q

what did Eskin discover?

A

brain site responsible for entrainment of sparrow clock

56
Q

what did Gaston discover?

A

pineal gland important for rhythmicity (avian)

57
Q

what did Zimmerman discover?

A

rhythmicity transferrable via pineal gland grafting (avian)

58
Q

what did Takahashi discover?

A

SCN important for rhythmicity, pineal gland releases melatonin for sleep (avian)

59
Q

what did Cassone discover?

A

norepinephrine can entrain the pineal gland rhythm, melatonin causes phase shifts in the SCN clock

60
Q

what is the mechanism of the pineal gland?

A

pineal gland contains photoreceptors that make its melatonin release cycle LD entrainable, norepinephrine can also entrain the release of melatonin

61
Q

what is the circadian clock mechanism of anolis carolinesis?

A

pineal releases melatonin rhythmically, pineal gland is both output of system and part of system

62
Q

what is the mammalian circadian clock mechanism?

A

SCN (specifically dorsomedial) most important oscillator, other oscillators include retina, raphe nuclei, food, meth, time memory

63
Q

how do we know SCN is the clock?

A

location, ablation, transplantation, explantation, tau hamster transplant (Lucy Always Tries Every Taco)

64
Q

what is ablation?

A

experimentation on individuals with destroyed/damaged SCNs

65
Q

what is explantation?

A

rhythms can be measured from SCN in vitro

66
Q

why is the mammalian pineal gland different?

A

it is not photosensitive

67
Q

what is melanopsin?

A

unique mammalian photopigment

68
Q

how does photic information reach the SCN in mammals?

A

photoreceptors in ganglion cells of retina, large receptive fields project to SCN via retinohypothalamic tract

69
Q

T or F: all vertebrates have pacemakers in pineal gland

A

FALSE AF

70
Q

T or F: electrical stimulation of IGL creates nonphotic phase shifts in hamsters

A

TRUE

71
Q

T or F: melanopsin is a neurotransmitter in the mammalian RHT

A

FALSE

72
Q

T or F: NPY is a neurotransmitter in the mammalian RHT

A

FALSE

73
Q

T or F: melatonin is required for behavioural rhythmicity in hamsters

A

FALSE

74
Q

T or F: hamsters without a dorsomedial SCN can still entrain to LD cycles

A

FALSE

75
Q

what happens after complete ablation of the SCN in rats?

A

arrhythmicity

76
Q

what happens after NPY is injected during subjective day?

A

mimicry of effects of novelty induced wheel running

77
Q

T or F: humans exhibit more than one circadian oscillation

A

TRUE

78
Q

what can block effects of novelty induced wheel running?

A

physical restraints (WOW DUH)

79
Q

what did Kalmur demonstrate?

A

clock is metabolically based and endogenous

80
Q

what will a perfectly temperature compensated clock have?

A

Q10 of 1

81
Q

what phenomenon is not included in Aschoff’s rules?

A

when light intensity increases diurnal animals will decrease activity

82
Q

T or F: for an animal with tau = 23 hrs each circadian hour is longer than a real hour

A

FALSE

83
Q

T or F: Bunning’s temp experiments demonstrated that clocks are temp dependent

A

FALSE

84
Q

T or F: an animal with tau = T has a clock that is not responsive to light

A

FALSE

85
Q

T or F: nocturnal and diurnal animals are active in their subjective day

A

FALSE

86
Q

T or F: an organism with tau = 25 hrs needs a 1 hr advance each day to entrain to a 24 hr T

A

TRUE

87
Q

what is the significance of the phase angle?

A

determines animal’s activity relative to a stable zeitgeber

88
Q

why does tau not equal 24hrs?

A

organism will not be able to adapt well to any environmental stressors

89
Q

if the limit of entrainment is +/- 3hrs, how would an organism with tau - 27hrs entrain to a 22hr day?

A

using nonphotic that compound with photic stimuli the entrainment can go past the limit

90
Q

what is the common element of nonrhotic, phase shifting stimuli?

A

behavioural activation or arousal

91
Q

what neurotransmitter does the PPT release into the IGL?

A

acetylcholine

92
Q

what are the effects caused by pineal gland lesions in sparrows?

A

arrhythmicity in DD

93
Q

in what species what the first clock mutant identified?

A

drosophila

94
Q

T or F: lizard clock is located in pineal gland

A

FALSE

95
Q

T or F: mice without eyes are rhythmic in LD cycles

A

TRUE

96
Q

what is the effect on human free running period after lesioning the raphe nuclei?

A

free running period continues

97
Q

where are photoreceptors found in avian tissue?

A

pineal gland and deep brain tissue

98
Q

T or F: person flown from Toronto > Vancouver needs 3hr delay to entrain

A

TRUE

99
Q

T or F: in some mammals the pineal gland can function as a clock

A

FALSE

100
Q

T or F: tau mutant clocks run slower

A

FALSE (faster)

101
Q

what happened in Ralph’s tau mutant experiment? (so obnoxious to reference himself ew)

A

giving a hamster an SCN lesion caused arrhythmicity, when fetal tau mutant SCN transplanted into lesioned hamster, hamster displayed tau mutant behaviour of donor

102
Q

why are clocks not equal in period to the cycle that entrains them?

A

when days are short the phase angle of entrainment can drift because long as light continues to fall during subjective day, there will be no effect on phase shift or entrainment; biological variability causes a rhythm close to ZT to have a slightly different period

103
Q

what are 4 major biological clocks?

A

circadian, circannual, circatidal, circalunar

Biological Rhythms (2 decks)

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