231 Describe how our biological rhythms influence our daily functioning Circadian Rhythms repeating fluctuations such as sleeping and waking that occur over a period of twentyfour hours ID: 776666
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Slide1
UNIT 5 – STATES OF CONSCIOUSNESS
Slide2Slide323.1 – Describe how our biological rhythms influence our daily functioning.
Circadian Rhythms
: repeating fluctuations, such as sleeping and waking, that occur over a period of twenty-four
hours
. An “internal clock” located in the
hypothalamus
, the
suprachiasmatic nucleus
, monitors
circadian
rhythms. The suprachiasmatic nucleus receives information from ganglion cells
located
in the retina that send information based on whether it is light or dark out. In
response
, neurons in the
suprchiasmatic
nucleus trigger the release of a hormone called
melatonin
, which is produced in the pineal gland. When the ganglion cells detect darkness and
melatonin
is released, the individual experiences tiredness. When it starts to become
light outside
,
melatonin
decreases, helping the individual wake up. This “internal clock” makes it
possible
to maintain circadian rhythms regardless of external cues. Environmental factors can
disrupt
circadian rhythms (“jet lag”). Taking melatonin supplements can lessen the symptoms
of
jet lag; such supplements are also common treatment for insomnia.
Slide423.1 – Describe how our biological rhythms influence our daily functioning.
Sleep
: periodic, natural loss of consciousness – as distinct from unconsciousness resulting from a coma, general
anesthesia
, or hibernation.
Slide523.2 – Describe the biological rhythm of our sleeping and dreaming stages.
Brain Waves
:
A
person who is awake and attentive shows brain activity through
beta waves
. A person who is awake but inattentive would show
alpha waves
.
Theta waves
follow alpha waves and indicated even slower brain waves.
Delta waves
show low brain activity and are associated with deep sleep
.
About
every 90 minutes we pass through a cycle of four distinct sleep stages.
Slide623.2 – Describe the biological rhythm of our sleeping and dreaming stages.
Stages of Sleep
NREM
Stage 1
:
Brain
waves:
-
Alpha and Theta waves
Characteristics
:
-
Lasts only a few minutes
-
Person can quickly gain consciousness.
-
Experiences hypnagogic hallucinations – vivid sensory experiences.
The
most common hypnagogic
hallucination
is the sensation of
falling
, which is accompanied by myoclonic jerk – an involuntary
muscle
spasm throughout the body that often awakes the person.
Slide723.2 – Describe the biological rhythm of our sleeping and dreaming stages.
Stages of Sleep
NREM Stage 2
:
Brain
waves:
-
Theta and the start of Delta waves
Characteristics
:
-
Start of true sleep
-
Sleep spindles
in EEG patterns – sudden bursts of brain activity.
Slide823.2 – Describe the biological rhythm of our sleeping and dreaming stages.
Stages of Sleep
NREM Stage 3
:
Brain
waves:
-
Delta brain waves
Characteristics
:
-
Considered NREM Stage 4 when delta waves exceed 50 percent of
brain
activity. Person does not
experience
sensory stimulation – hard
to
wake up.
-
Referred to as slow-wave sleep (or S-sleep).
Slide923.2 – Describe the biological rhythm of our sleeping and dreaming stages.
Stages of Sleep
REM
Sleep
Brain
waves:
-
Beta brain waves
Characteristics
:
-
Brain activity becomes more active, resembling that of an awakened state; approximately
85 percent
of dreams occur during this stage.
-
Muscle activity is suppressed (referred to as “
muscle
atonia
”).
-
Physiological arousal is high – heart rate, blood pressure.
-
Eyes move rapidly back and forth beneath eyelids – Rapid Eye Movement (also called
paradoxical sleep
).
Slide10Slide1123.2 – Describe the biological rhythm of our sleeping and dreaming stages.
With each 90-minute cycle, NREM Stage 3 sleep decreases and the duration of NREM Stage 2 and REM sleep increases.
Over the course of a person’s lifetime, NREM Stages 3 and 4 gradually decrease. In fact by late adulthood, most individuals average only about 20 minutes in these stages as compared to the young child, who spends two or more hours in NREM Stages 3 and 4.
Slide12Slide1323.3 – Explain how biology and environment interact in our sleep patterns.
What affects our sleep patterns?
Suprachiasmatic
Nucleus – light triggers the suprachiasmatic nucleus in the
hypothalamus
to decrease the
hormone
melatonin. Nightfall triggers an increase
of
melatonin.
2
) Environmental Impacts on Sleep:
-
Artificial light delays sleep
-
Irregular sleep schedules (weekends vs. School/work days)
-
Shift work, social media, and other modern diversions cause us to stay up
later
than past generations.
Research shows that genetics also impacts the amount of sleep each individual needs.
Slide1423.4 – Describe sleep’s functions.
Why do we sleep?
-
Researchers know that sleep is important.
-
We spend 1/3 of our lives sleeping.
-
If an individual remains awake for several days, immune
function
and concentration deteriorates and the risk
of
accidents
increases.
Slide1523.4 – Describe sleep’s functions.
Sleep Theories
1) Sleep
protects: sleeping in the darkness when predators loomed about
kept
our ancestors out of harm’s
way
.
2
) Sleep helps us recuperate: sleep helps restore and repair brain tissue.
3
) Sleep helps us remember: sleep restores and rebuilds our fading.
4
) Sleep feeds creative thinking: a complete night’s sleep boosts our thinking
and
learning. Sometimes dreams
inspire
noteworthy achievements.
5
) Sleep supports growth: during sleep, the pituitary gland releases growth
hormone
. Older people release
less
of this hormone and also spend less
time
in deep sleep.