w6) disorders of sleep wake cycle Flashcards
Which brain area regulates circadian rhythms?
how many hrs is the rhythm in humans? diurnal animals? nocturnal animals?
SCN, hypothalamus
humans 24.18 hrs (approx bit more than 24)
diurnal (day) > 24 hrs
nocturnal (night) < 24 hrs
humans have approx 16 hrs awake, 8 hrs asleep
What 2 components does the circadain cycle depend on?
hint: syncing internal and external component
1) SYNC of the endogenous clock (internal)
to 2) external L-D cycle
What are 3 components animals/humans can entrain/sync the circadian cycle to LD cycle with?
- light
- non-photic/light signals
- melatonin (modulate)
entrain component #1
how does light entrain? what NT released as output? what wavelength? input or output to SCN core? what photopigment? which track?
what occurs if LD CYCLE intensity/length overall too short/long to entrain? (hint: what rhythm)
retina recieves light input
into SCN core
output Glutamate
short blue wavelength
melanopsin photopigments, RGC
RHL (retino hypothalamic tract)
FREE RUNNING RHYTHM
entrain component #1
what does the phase respone curve (PRC) show?
hint: regarding phase shifts
direction and magnitude of phase shift
depending on light
entrain component #2
3 examples of non-light/photic signals we can use to entrain circadian rhythm to LD cycle?
- social cues
- mealtime
- bed time scheduled
entrain component #3
what is melatonin? which brain region controls it? where is it released?
help inc what components of sleep?
help treats which 2 main disorders?
hormone controlled by SCN, released in pituitary gland
helps sleep propsnesity, rhythms phase
treat circadian (sleep wake) disorders
treats insomnia
Name 3 main causes (general) of circadian (sleep wake rhythm) disorders.
ex: changes in x relation to y
ex: changes in x relation to y
ex: dysfunction in
1) CHANGES IN LD CYCLE in relation to internal clock (shift work, jetlag)
2) CHANGES IN INTERNAL CLOCK in relation to LD cycle (non-24, delayed/advanced)
3) internal clock dysfunction (irreg sleep wake rhythm)
disorder category #1 changes in LD CYCLE in relation to internal clock
name 1 disorder of LD CYCLE changes in relation to internal clock
shift work disorder
disrupted LD CYCLE change related to internal clock: shift work disorder
name 1 cause
name 3 symptoms
cause = given night shifts
low concentration/fatigue, insomnia, mental/physical complaints
disrupted LD CYCLE change related to internal clock: shift work disorder
treatments for shift work disorder
- cues include?
- schedule?
- meds?
- therapy?
- improve cues - diet, exercise, bedtime = FOCUS ON TIMING of cues
- avoid shift work, attempt better fixed schedule of LD cycle in sync to wake/bed time
- melatonin
- light therapy
disrupted INTERNAL CLOCK CHANGES relation to LD cycle
Name 3 types of circadian rhythm disorders which internal clock is changed due to LD cycle.
1) non-24 hr cycle disorder
2) delayed sleep-wake phase disorder
3) advanced sleep-wake phase disorder
disrupted internal clock changes (due to LD) ex 1) NON-24 HR disorder
symptoms - x is misalligned to y? what changes everyday?
is phase stable everyday?
insomnia or excessive sleepiness symptoms?
hint: if “normal SW cycle=24” what is non-24?
SW cycle misalligned to circadian system = time to sleep changes everyday/non-fixed
ex: 9 am-2pm –> 3 pm-8pm etc
phase UNSTABLE relation to LD cycle
both insomnia and sleepy
disrupted internal clock changes (due to LD) ex 1) NON-24 HR disorder
if 24 hr clock is rectangles stacked on top of each other on a graph.. what is a non-24 hr disorder look like on a graph?
shifting rectangles diagonally
disrupted internal clock changes (due to LD) ex 1) NON-24 HR disorder
Is sensitivity to light high or low in non-24 hr disorder patients?
what hormone is dec/absent?
2 disorders/conditions examples?
hint: think whenever I want
VERY LOW sensitivty to light
(think: can be going to sleep at 10 am bright daytime light)
melatonin little/none
depressive patients
blind patients
