w8) impact of circadian disruptions

Question 1

how circadian system impact sleep and alertness

What 2 aspects of sleep is impacted by circadian system disruption?

Answer 1

1) sleep longevity = life span inc w SCN, if c rhyhtm disrupted - shortens lifespan
2) sleep contrlled by process S and C

Question 2

What happens to the c. rhythm when fetal SCN is transplanted to hamsters?

Answer 2

restored back to 24 hrs
inc lifespan

Question 3

What happens to the c. rhythm when external light is disrupting it?

Answer 3

SHORTERNS life span

Question 4

What process controls sleep and circadian rhythm?
peak of circadian wake in?
peak of circadian sleep in?

Answer 4

Process S- homeostasis, pressure, drive load
Process C - circadian 24 rhythm
peak of circadian wake in evening
peak of circadian sleep in early morning

Question 5

Process C - circadian 24 rhythm
drive for wake opposes? help maintain ?
drive for sleep opposes? help maintain?

Answer 5

drive for wake opposes sleep - help maintain wake

drive for sleep opposes wake - help maintain sleep

Question 6

Jessy has persistent sleep onset insomnia due to an abnormally delayed circadian clock. What is likely to be happening?

a. Her homeostatic build-up is too slow, resulting in delayed sleep pressure
b.Her sleep time is too early in her biological day, resulting in an attempt to sleep in the “wake maintenance zone”
c.Her core body temperature minimum is too early in her sleep period to allow her to fall asleep
d.Her clock is unable to entrain to the light/dark cycle, causing cyclical misalignment

Answer 6

B

Question 7

Men and women (on average) have different clocks. How different?

a.
Women have clocks that desynchronise more easily from sleep, leading to more irregular sleep
b.
Women have a more delayed melatonin rhythms, likely leading to later sleep
c.
Women have a more advanced melatonin rhythms, likely leading to earlier sleep
d.
Women have longer circadian periods, leading to earlier sleep timing

Answer 7

C

Question 8

**impacts on metabolism

What are 3 sleep problems that cause metabolism disruptions?

Answer 8

1) insuffcient little sleep
2) circadian clock to behavior misalligned
3) circadian disruptions (light disrupting clock)

Question 9

**impacts on metabolism

What are metabolism issues/results from insufficient sleep, circadian misalligned to behavior, and light disrupting the c.system?

what 1 thing inc?
what 3 things dec?

Answer 9

INC BMI level, fatter for both genders
DEC - glucose tolerance/insulin sensitivty, signals for full (leptin), reswting metabolic rate

Question 10

**impacts on metabolism

hormone for hunger
hormone for full/satiated

Answer 10

ghrelin (stomach grrrumbling)
lepin (full)

Question 11

** impact of cardiovascular health

What are 1 main sleep problem that cause/inc CVH health disruptions?

Answer 11

c rhythm disturbances
light at night exposed/shift workers –> disrupt rhythm –> inc CVD risk

Question 12

Heart attacks are most likely to occur at what time of day?

early daytime, nightime, midday, anytime

Answer 12

early daytime

Question 13

what types of people have inc risks of cardiovascular health disruptions related to sleep?

Answer 13

shift workers

Question 14

What is the most likely common underlying factor increasing vulnerability to a broad range of diseases in shift workers?

a. Chronic exposure to light at night disrupting circadian rhythms
b.Increased preference for unhealthy foods
c. Suppression of melatonin at night and increased melatonin in the day
d.Less overall sleep duration

Answer 14

A

Question 15

** impacts on cancer

What are 2 main sleep problems that cause/inc cancer or tumor growth disruptions?

Answer 15

1) dec melatonin (due to light disruptions at night)
2) jetlag schedules

Question 16

** impacts on depression

which 2 phases of the circadian rhythm graph is assoicated with DERESSION?

higher or low of those 2 phases?

Answer 16

amplitude
phase
BOTH LOWER/FLATTER in depression than controls

Question 17

mental health impacts

Seasonal affect disorder (depression related) have what types of phases?
what mood is associated to it?

Answer 17

advanced or delayed subjects = WORSE MOOD
closer to idea/non late or early subjects = BETTER MOOD

Question 18

mental health impacts

Major depressive disorder patients have what types of melatonin?
circadian alligned or misalligned?
light sensitivty high or low?

Answer 18

DELAYED melatonin secretion - symptoms worsse
MORE circadian misalignment
LOWER light sensivity

Question 19

if MDD patients have lower light sensitivity, what are treatment options?

Answer 19

SSRI and light therapy - inc light sensitivty in patients

Question 20

patients with bipolar disorder have ? sensitivity to light?

Answer 20

HGIHER

Question 21

low/high daytime light and low/high night time light = poorer mental health

hint: do depressive patients like light exposure in daytime?

Answer 21

lower daytime light
more night time light

Question 22

treatment methods to improve mood:
light exposure? when?
melatonin to help adjust who?
medication to inc/dec light sensitivty?

Answer 22

light at daytime (to help advance the delayed indivudals)
light at evening (to help delay the advanced indivudals)
adjust melatonin- help ADVANCE - sleep ealrier promoting
SSRI - inc light sensitivity

Question 23

positive effects of daytime light?

Answer 23

enhance mood
inc amplitude

Question 24

neg effects of light at night?

Answer 24

disrupted c system
disrupted sleep

Question 25

You read a story claiming that experimental sleep restriction impacts metabolic function. The conclusion is that less sleep ITSELF is the cause. What is a key issue here?

a.Individual differences in sleep need is rarely considered
b.Sleep restriction can itself cause disruptions of the circadian system
c.Sleep restriction is often accompanied by turning on lights during the night, potentially disrupting the circadian system
d.Sleeping in a lab setting is almost always poor (lots of wires, etc.)

Answer 25

C - many reasons associated, not only sleep itself