LMBR8: SLEEP 1 B P 256-269 Flashcards

Question

How is melatonin secretion regulated by the SCN? BR 262 & 263

Answer 1

a) Retina Ganglion Cells, melonopsin =\> Neuronal Tract =\> SCN =\> Central oscillators entrained =\> Neuronal Tract to Pineal Gland =\> Melatonin secretion - Melanopsin- photopigment in RGC, maximally sensitive to short wavelengths of light- Blue light. Amount of melonpsin relays light intensity and spectra to SCN which affects timing of melatonin secretion. AKA Light =\> less melonopsin =\> decrease melatonin Dark =\> more melonopsin =\> increase melatonin b) SCN =\> Sphlanic nerves =\> adrenal gland =\> secretes epinephrine, norepinephrine, glucocorticoids, and aldosterone =\> regulates blood flow, temperature and food intake =\> Melatonin, biofeedback loop =\> adrenal gland

Answer 2

1) Light intensity 2) Light wavelength (frequency, color) 3) Food (carbohydrates) 4) Fluid (blood osmolality-sodium, potassium, chloride in the plasma) 5) Ambient temperature

Answer 3

C - Cutaneous blood flow is an operator. Cutaneous fat stores which affect core and extremity temperature, and vascular tone, which affects fluid volume modifying core and peripheral temperatures, are additional modifiers. Pupillary reflex limits the amount of light getting to retina ganglion cells. Sunglasses or back light on electric devices change the intensity of light reaching retina ganglion cells. SNPs (single nucleotide polymorphisms) are genetic variations in the DNA. They can occur in PER & CRY proteins, which are integral in controlling the circadian rhythm.

Answer 4

True. Cutaneous fat stores affect core and extremity temperature. If there is too much, itdampens the bodies ability to thermoregulate. If there is not enough, it accelerates it.

Answer 5

They inhibit function of other proteins, like the proteins regulating the “clock” and “cycle” of sleep, until they degrade in 24hrs. Light exposed to retinal ganglion cells produces more PER protein. If SNMs occur in PER and CRY proteins causing them to function inappropriately, the circadian rhythm may not work.

Answer 6

A- Nitric oxide and estrogen enhance vasodilation and lowers blood pressure. Sodium causes acute vasoconstriction and raises blood pressure.

Answer 7

1) Core body temperature changes 2) Melatonin suppression or secretion 3) Cortisol secretion, timing of cortisol spike 4) Increased or decreased cutaneous blood flow

Answer 8

1) Alertness 2) Kinetic activity 3) Motor skills, including precision 4) Strength and stamina

Answer 9

1) Early sleep 2) Awakening 3) Throughout sleep 4) Onset 5) Onset 6) Early sleep 7) Late sleep 8) Throughout sleep 9) Onset 10) Late sleep 11) Throughout sleep 12) Early sleep 13) Onset 14) Late 15) Onset 16) Throughout sleep 17) Early sleep 18) Late sleep 19) Early sleep

Answer 10

A- As melatonin levels rise, core temp decreases and sleep propensity increases

Answer 11

Light. Light intensity, Light spectra, timing of light exposure in 24hr cycle, duration of light exposure

Answer 12

1) 100K lux 2) 25K lux 3) 2K to 10K lux 4) 1K to 5K lux 5) 200 to 500 lux 6) 50 to 200 lux 7) 50 lux 8) 20 lux 9) 1 lux 10) 0.001-0.0001 lux (8 orders of magnitude less than bright sunny day)

Answer 13

Kelvin color is a number that describes the dominant color tone produce at a certain temperature in Kelvin. Lower temperatures in Kelvin lead to warmer colors of light (red, orange). Higher Calvin temperatures lead to cooler lights (blue, violet).

Answer 14

Blue light at night time increases cortisol, nighttime heart rate, blood pressure, sympathetic tone and core body temperature. It suppresses melatonin. It decreases sleepiness and causes alertness, inhibiting sleep onset and shifts the sleep cycle later. Examples include back lit computers, TV screens, phones, and other screens as these have strong blue spectra components. Also typical night time household lighting of intensities 50 to 100 Lux.

Answer 15

Light during the day suppresses melatonin and supports alertness. Low daylight decreases daytime activity, alertness, positive affect, core body temperature amplitude/max and increases melatonin suppression with evening light. Low daytime light significantly increases the sensitivity of melatonin suppression from late at night. Daytime exposure of 10 K Lux of light for 6.5 hours cannot fully eliminate night time melatonin suppression from exposure to 90 lux of light. If low light exposure has occurred 2 to 3 days prior, the SCN is more sensitive to light at night, resulting in higher melatonin suppression, possible delayed onset of sleep, and shifting of the sleep cycle.

Answer 16

The ideal SCN clock is 24 hour circadian rhythm with consistent sleep and wake times. It was traditionally naturally reset by the solar cycle of day/night. It is now more difficult to reset due to inappropriately timed light signals from electricity (lights).

Answer 17

a) Delayed b) Advanced c) Delayed d) Advanced e) Advanced f) Delayed g) Delayed h) Delayed i) Advanced j) Delayed k) Advanced l) Delayed

Answer 18

24hrs and 8min. 5 to 15

Answer 19

If shorter than 24 hours, advancement of ~10 minutes or less is needed. Example, delaying exposure in light in morning by 10 minutes or ideal wake up time. If longer than 24 hours, backward setting of ~ 20 minutes or less is needed. Example, limiting light 20 minutes earlier in evening so ideal bedtime can be achieved.

Answer 20

Decreased daytime activities/attention, positive affect, social ability, REM sleep, and melatonin. Metabolic effects include decreased caloric burn, leptin (appetite control hormone) and core body temperature amplitude/max; increased appetite and insulin resistance.

Answer 21

Skipped, late, or low-carbohydrate breakfast lead to diminished cortisol awakening rise. Eating breakfast shortly after awakening may help shift wake-up time earlier. Eating a high carb breakfast may improve sleep-wakefulness transition. Eating dinner too early may contribute to falling asleep too early. - To shift carbohydrates if someone is falling asleep too early, they can eat more carbohydrates at dinner. If someone is falling asleep too late, they can shift carbohydrates to earlier meals, avoid snacking and carbohydrate rich dinners, and eat an earlier dinner.

Answer 22

Body temperature is controlled by three main elements: 1) the heat producing body core, which is generally homeostatic 2) the heat losing peripheral body, which varies widely in temperature in response to blood flow 3) the ambient temperature of the surrounding environment - Normally, during the afternoon, core body temperature will rise and peripheral extremities will cool. During the night, the opposite will occur as heat shifts from the core to the peripheral extremities and heart rate and cardiac output are reduced.

Answer 23

In late afternoon, higher blood osmolality leads to higher afternoon peak core body temperature because of an increase in internal temperature threshold, increased blood flow the vital organs and less output to the peripheral body. Decreased fluid volume can reduce amount cutaneous blood flow needed for core cooling at night; and increases cardiac activation, sympathetic tone which shunts blood to core.

Answer 24

1) True 2) False - Ambient temperature is a strong determinant of peripheral body temperature. 3) False - Benzodiazepines, yoga, non-sleep meditation and autogenic training all produce a similar effect in the body‘s natural shift of heat to the extremities. With these antecedents, blood is shunted from the core to the extremities as sympathetic activation in the muscles and skin, heart rate, and energy expenditure are all reduced.

Answer 25

a) ~20% b) ~40% c) ~45%

Answer 26

E- A 65-year-old has 50% lower retinal illuminance than a 45 y/o, not 25%

LMBR8: SLEEP 1 B P 256-269 Flashcards

Jayshri