Term
| Do cetaceans have SWS simultaneously in both hemispheres? |
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Definition
| Cetaceans = marine mammals swim while asleep and do not have Slow Wave Sleep in both hemispheres simulataneously. The eye contralat to the hemisphere with SWS stays closed, and other eye is opened |
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Term
| what is the primary daily entraining agent for our SCN clock? |
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Definition
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Term
| how long is our internal clock? |
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Definition
| 24.18 hours. therefore, we have to entrain our SCN clock to be synchonized to the 25 hour photoperiod cycle. |
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Term
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Definition
| melanopsin is a protein/photoreceptor that measures the intensity of light. |
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Term
| Where are melanopsin cells found? |
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Definition
| In retinal ganglion cell layers |
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Term
| What do melanopsin cells do? |
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Definition
| melanopsin cells ensure that light is the primary entraining agent for our internal clocks |
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Term
| How do melanopsin cells function? |
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Definition
| melanopsin cells transmit info about the environmental timing of Earth's light via the retinohypothalamic tract to the SCN. |
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Term
| Are melanopsin cells part of rods and cones that transmit visual info via the optic tract to the THAL and occipital lobe? |
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Definition
| No, melanopsin cells are completely unique from rods and cones. |
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Term
| State the circadian pathway |
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Definition
| Light-->melanopsin cells-->(via the retinohypothalamic tract)--> suprachiasmatic nucleus (SCN)--> paraventricular nuclei--> superior cervical ganglion--> pineal gland, which secretes melatonin in darkness, but whose secretion is inhibited in the light. |
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Term
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Definition
| Suprachiasmatic nucleus = biological clock |
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Term
| What does the SCN act as a "master regulator" for? |
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Definition
| It entrains all other peripheral physiological oscillators. |
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Term
| How does the SCN control all other peripheral physiological oscillators? |
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Definition
| Via neural connections to other brain regions, through control of melatonin secretion, and via cortisol, thyroid, GH, leptin via its influence of the pituitary gland. |
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Term
| what horomones are controled via circadian rhythms? |
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Definition
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Term
| Does it matter whether or not we are assleep as to whether the SCN can control melatonin and cortisol? |
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Definition
| No. this is a circadian controlled process for certain horomones. |
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Term
| what regulates sleep need? |
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Definition
| circadian system interacting neurobiologically with homeostatic systems and physiological mediators |
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Term
| Circadian clock (SCN) is primarily a BLANK promoting system? |
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Definition
| SCN= wake promoting system |
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Term
| What does the SCN ensure? |
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Definition
| The SCN ensures that the organisms remains awake. |
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Term
| At night (dearth of light), SCN BLANKS its waking system, permitting a drive for BLANK to be expressed. |
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Definition
| At night (dearth of light), SCN WITHDRAWS its waking system, permitting a drive for SLEEP to be expressed. |
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Term
| How does sleep drive build up/dissapate? |
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Definition
| Sleep drive is a homeostatic system--NOT AN OSSILATOR--as such it build up and dissapates relative to the quantity and quality of sleep we obtain |
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Term
| Sleep drive is a BLANK system, not an ossilator |
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Definition
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Term
| Is circadian drive an ossilator or a homeostatic system? |
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Definition
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Term
| If sleep drive is not adequately satisfied physiologically, what happens? |
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Definition
| The homeostatic drive for sleep can build to a point at which the Circadian system can't maintain wakefullness --> MICROSLEEPS and SLEEP ATTACKS |
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Term
| When is sleep most likely to occur? |
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Definition
| Sleep is most likely to occur and to progress into deeper stages and be sustained for longer duration when circadian system = Oscillating DOWN its waking drive + pressure for sleep is building UP. |
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Term
| what happens when pressure to sleep is exagerated? (eg--being awake for >16hours) |
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Definition
| fall asleep rapidly, progress into deepest stages of sleep quickly, have lower resting metabolic rates during sleep and greater EEG slow wave activity (SWA), and sleep duration is longer |
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Term
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Definition
| Electrooculogam (EOG) measures eye movements |
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Term
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Definition
| EMG (electromyograms) measure muscle activity |
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Term
| What is PSG? What does it consist of? |
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Definition
| PSG = polysomnography = EEG, EOG, EMG, ECG, respiration, and behavioral observations |
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Term
| What is the sleep switch? |
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Definition
| The VLPO--the ventrolateral preoptic nucleus |
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Term
| What happens when the VLPO hyperpolarizes the THAL? |
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Definition
| decrease in afferent flow to the cortex, decrease in normal executive attention (unstable), brain slips offline |
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Term
| What obstructions does sleep apena provide? |
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Definition
| OSAS prevents normal consolidation of sleep and progression through deeper sleep stages |
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Term
| What is the hallmark of inadequate sleep? |
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Definition
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Term
| What do lapses demonstrate? |
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Definition
| The dynamic interaction of circadian pacemaker (promote wakefulness at certain times of day) and homeostatic drive for sleeep. |
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Term
| Is lapsing better or worse at 24 hours or 36 hours of wakefulness? Why? |
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Definition
| Lapsing is worse at 24 hours because your circaidian wake signal is stronger at 36 hours than at 24 hours |
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Term
| what happens when sleep deprived?q |
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Definition
| state instability occurs-- the sleep system manifests itself in uncontrolled interruptions of waking attention and alertness |
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Term
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Definition
| sleep propensity = sleepiness |
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Term
| As homeostatic sleep drive increases, what happens to latency from wake to stage 1 non REM sleep to stagte 2 to SWS(deep non REM sleep_? |
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Definition
| This transition gets exponentially faster. |
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Term
| what is state instability? |
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Definition
| sleep system turning on in presence of waking drive--sudden unexpected delays in brain's response - "lapses" |
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Term
| when does state instability occur? |
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Definition
| when a healthy adult has been awake for more that 16-18 hours |
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Term
| What are 2 hallmark feature of sleep onset? |
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Definition
| rolling eye movements (eye rolls right and upward) and slower eyelid closures. "microsleep" |
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