Textbook Notes (363,452)
Canada (158,372)
Psychology (9,573)
PSYA01H3 (1,196)
Steve Joordens (1,052)
Chapter 5

Chapter 5 textbook notes.docx

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University of Toronto Scarborough
Steve Joordens

Chapter551BiologicalRhythmsofConsciousnessWakefulnessandSleepConsciousnessa persons subjective awareness including thoughts perceptions experiences of the world and selfawarenessChanges in our subjective experiences make consciousness very curiousWHATISSLEEPHumans spend 13 of their lives sleepingCircadianRhythmsOrganisms have evolved biological rhythms that are neatly adapted to the cycles in the environmentoEx Bears hibernate during winterCircannual rhythmyearly cycleCircadian rhythmsinternally driven cycles of approximately 24 hours affecting physiological and behavioral processesoInvolve the tendency to be asleep or awake at specific times to feel hungrier and even concentrate betteroWe tend to get most of our sleep at night because our circadian rhytms are regulated by the daylight interacting with our nervous and endocrine systemsoOne key brain structure in this processsuprachiasmatic nucleus SCN of the hypothalamusCells in the retina of the eye relay messages about light levels in the environment to the SCNSCN then communicates signals about light levels with the pineal glandPineal gland releases melatonin which peaks in concentration at nighttime and is reduced during wakefulnessAs such light is the primary stimulus for the human circadian rhythmFor some people this system is disruptedPeople with blindness due to retinal damage cannot send light signals from the retina to the SCN and pineal gland and their circadian rhythms dont synchronize to daynight cyclesHowever they can be adjusted with doses of melatoninCircadian rhythms appear to change with ageWe need much less sleep especially REM as we move from infancy to early childhood to adulthoodPeople generally experience a change in when they prefer to sleepPeople show higher alertness and cognitive functioning during their preferred time of dayTheStagesofSleepPolysomnographyset of objective measurements used to examine physiological variables during sleepoEx Devices that measure respiration and body temperature thermometeroElectrical sensors attached to the skin measure muscle activity around the eyes and other parts of the bodyoSleep cycles are most often defined by the electroencephalogram EEG that measures brainwavesOutput of an EEG is a waveformBeta waves are characteristic of wakefulnessIrregular nature reflects bursts of activity in different regions of the cortex and are often interpreted as a sign that a person is alertAs the begin to sleep the wages get slower larger and more predictablealpha waves signal that a person may be daydreaming meditating or starting to fall asleepEEG signals during sleep move through four different stagesStage 1brain waves slow down and become higher in amplitude theta wavesBreathing blood pressure and heart rate all decrease slightly as the individual begins to sleep
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