Why Do we Sleep and Dream?

Question 1

inherent timing mechanism that controls or initiates various biological processes

Answer 1

biorythym

Question 2

biorhythms are linked to

Answer 2

cycle of days and seasons produced by earths rotation around the sun

Question 3

humans largely evolved as ________ animals and our behaviour is dominated by _______ ______ of daylight activity and nocturnal sleep

Answer 3

• equatorial

- circadian rhythm

Question 4

do biorhythms regulate metabolic activity?

Answer 4

yes

Question 5

rhythms are _____

Answer 5

endogenous (come from within)

Question 6

neural systems that times behaviour

Answer 6

biological clock

ex birds migrate before it gets cold

Question 7

biological clocks synchronize behaviour to the _____ _____ of a real day and makes ________ about tomorrow

Answer 7

• temporal passage

- prediction (allows us to prepare physiologically and cognitively)

Question 8

biological clock regulates: (4)

Answer 8

feeding time, sleeping time, metabolic activity, regulate gene expression

Question 9

circadian =
circannual=
infradian =
ultraradian =

Answer 9

daily
yearly
less than a year
less than a day

Question 10

rhythm of the body’s own devising in the absence of all external cues
ex?

Answer 10

free running rhythms

- biological clock in the absence of light

Question 11

without input from external cues, our body has its own rhythm with a period of ___ to ___ hours

Answer 11

25 to 27 hours

Question 12

animals expand and contract their sleep period as?

Answer 12

sleep related lighting period expands or contracts

Question 13

hamsters are _____

• in constant darkness, free running periods are _____ than 24 hours
• constant light, they are _____ than 24 hours

Answer 13

nocturnal

• shorter
• longer

Question 14

sparrows are _____

• in constant darkness, free running periods are _____ than 24 hours
• constant light, they are _____ than 24 hours

Answer 14

diurnal

• longer
• shorter

Question 15

environmental event that entrains the biological rhythms; a time setter; the property that allows entrainments of a biological clock

Answer 15

zeitgebers

ex, light resets the biological clock

Question 16

determines or modifies the period of a biorythm

Answer 16

entrainment

Question 17

a ______ allows an animal to synchronize its daily activity across the seasonal clock

Answer 17

entrained biological clock

Question 18

light pollution and jet lag are examples of?

Answer 18

zeitgebers

Question 19

is harder to adjust when traveling eat - west or west to east

Answer 19

west to east

Question 20

persistant asynchronous rhythms are associated with ? (5)

Answer 20

• altered sleep
• altered temp rhythm
• fatigue
• stress
• reduced success by sport teams

Question 21

main pacemaker of circadian rythms; located just above the optic chiasm
- the master clock

Answer 21

suprachiasmatic nucleus

Question 22

the _____ and the ____ also display clocklike activity (brain regions)

Answer 22

intergeniculate leaflet and pineal gland

Question 23

nearly every cell int he body has its own ?

Answer 23

clock

Question 24

the SCN is close to what?

and the cells of the SCN are more active (increased metabolic and electrical activity) when?

Answer 24

light information in the brain

- in the light period

Question 25

if the SCN is damage what happens

Answer 25

daily activities occur haphazardly

Question 26

SCN neurons maintain rhythmic activity in the absence of

Answer 26

input and output

Question 27

what happens if the SCN neurons are isolated from one another ?

Answer 27

each remains rhythmic but he rythmicity of some cells is different than that of other cells (needs to be sunchronizied in relation to each other to respond to environmental cues)

Question 28

neural route from a subset of cone receptors in the retina to the SCN - allows light to entrain rhythmic activity SCN

Answer 28

retinohypothalamic

Question 29

what are the 3 characteristics of the retinohypothalamic pathway

Answer 29

1. begins with specialized retinal ganglion cells that contain photosensitive pigments melanopsin 2. pRGCs axons bilaterally innervate SCN via retinohypothalamic tract 3. the retinohypothalamic tract activates core cells

Question 30

_____ neurons are not rhythmic but that entrain ___ neurons which are rythmic

Answer 30

core, shell

Question 31

these ganglion can respond to blue wave lengths of light even without getting info from the cones and rods

Answer 31

pRGCs (cores and shells)

Question 32

how do ppl who are congenitally blind(problem with rods and cones) maintain biological rhythms

Answer 32

still getting entrainment from blue wave length cells (pRGC) | --> cores and shells

Question 33

pathway of retinohypothalamic tract

Answer 33

1. photsensitive retinal ganglion cells respond to blue light 2. retinohypothalamic tract carries info about light changes to core cells in SCN 3. signal from SCN core neurons entrains shell neurons 4. SCN drives slave oscillators and recieved signals from the other brain and body areas

Question 34

SCN's circadian rhythm is usually entrained by?

Answer 34

morning light and evening light

Question 35

SCN can be disrupted or entrained by ? (4)

Answer 35

1. sudden changes in light 2. arousal 3. moving 4. feeding

Question 36

through which pathways do nonphotic events influence the SCN rhythm

Answer 36

intergeniculate leaflet and raphe nucleus

Question 37

what are the 2 groups of circadian neurons and what do they control

Answer 37

1. M- cells: control mornign activity and need light for entrainments 2. E- cells: control evening activity and need darkness for entrainment

Question 38

what may explain differences in morning people ad evening people

Answer 38

individual differences in genes and activity or circadian E or M cells (some ppl have more of one) - chronotypes are due to differences in SCN shell nuerons

Question 39

explain the feedback loops of circadian rhythms

Answer 39

proteins are first made and then combine, called a dimer for two proteins, which inhibits the production of its component proteins --> dimer then degrades and process starst again

Question 40

SCN pacemaker drives a number of ___________, each of which controls the rhythmic occurance of one behaviour (ex, body temp)

Answer 40

- slave oscillators

Question 41

SCN may drive slave oscillators via ? (3)

Answer 41

hormones, proteins, NT

Question 42

the master oscillator is where?

Answer 42

SCN

Question 43

4 functions of SCN cells in pacemaking circadian rhthyms

Answer 43

1. SCN neurons send axonal connections to nuclei close by in the hypothalamus and thalamus, which then pass on entraining signal 2. SCN connects with pituitary endocrine neurons to control hormones release to entrain many body tissues 3. SCN instructs autonomic neurons in the spinal cord to inhibit the pineal gland from producing melatonin 4. SCN cells themselves release hormones

Question 44

the SCN control melatonin release from the pineal gland so that melatonin circulates when? and does what?

Answer 44

- during the dark phase of the circadian cycle | - influences/ promotes rest and digest

Question 45

SCN control the release of ______ from the ________ so that they circulate during the light phase of the circadian cycle - this does what?

Answer 45

- glucocorticoids - adrenal gland - mobilizes glucose for cellular activity

Question 46

in rats, when melatonin is low in the lengthened spring time days, the gonads?

Answer 46

enlarge = more sex

Question 47

pacemaking produced by the SCN is a product of its ____ cells, which activate _____ _______ via both chemical and anatomical connections

Answer 47

shell cells, | slave oscillators

Question 48

when days are long, the SCN _____ melatonin secretion by the pineal gland, as days shorten, the melatonin _________ period _______ and the ________ period _______

Answer 48

- inhibits - inhibition, shortens - release period, lengthens

Question 49

cognitive events necessitate changes in gene expression, turning genes on or off --> as much as ___ % of the genome is under ________ _______ of the circadian rhythm

Answer 49

- 10% | - epigenetic control

Question 50

what serves a s good index for the time and place at which things should happen

Answer 50

time of day

Question 51

cognitive activities occur without the ? | - this means is ti adaptive for cognitive activity to occur?

Answer 51

SCN | - at the right time and place

Question 52

time of day can also account for our _________ _______ to daily events independent of the actual event

Answer 52

emotional response | - scared of the dark