The Normal Sleep Flashcards
defined as a physiological state of partial unconsciousness that is reversible, cognitive and perceptual disengagement from and to the environment are seen during this temporary unconsciousness, and from which the arousal is possible in response to any internal or external stimuli.
sleep
sleep’s effect on the body
Diminished activity of the skeletal muscles
Depressed metabolism
sleep is a state of unconsciousness that is _____, and this differentiates it from coma.
reversible
how to wake a sleeping patient properly
wake patient up inflict pain by pressing the nail bed and sternal rubbing
the person is not aware of the environment during sleep, so he does not ______ most stimuli during sleep.
perceive (although he may sense it)
Perception is different from –
sensation
when a sensory stimulus is consciously recognized it is considered as
perceived.
a sleeping person cannot take any conscious decision –
rather he reacts on instinct.
This explains why patients suffering from _____ when aroused forcibly often commit violent acts.
sleep-walking
It says that a person may be aroused with any
internal or external stimuli.
Internal stimuli that may arouse a person include
pain, anxiety or dyspnea.
External stimuli are often
auditory or tactile in nature.
are active during sleep unlike other organs
Brain, heart, and lungs
will continue functioning to keep respiration, heart rate and blood pressure normal during sleep
Brainstem
Lack of sleep leads to
drowsiness, lack of concentration, impaired memory and physical performance, reduced ability to perform basic functions
functions of sleep
restoration
energy conservation
Recovery or recuperation from illness
Restoration
restoration During NREM would promote
physical growth and healing
During REM stage, it is an important role in restoration of brain processes like
Attention span
Learning and memory
Emotional healing
Performing basic social skills
Increased energy use during wakefulness or wakeful hours must be offset by decreased energy consumed during sleep
energy conservation
Restore physical growth and healing of the body
energy conservation
Energy conservation theory
NREM declines with age
Energy requirement declines with age
Sleep has many important parameters:
the total duration of sleep
maintenance of sleep
at what time of the day we fall asleep
Two main Stages of Sleep
NREM- non-rapid-eye-movement
REM -rapid-eye-movement
3 stages of NREM
N1
N2
N3
Transition stage between drowsiness and sleep, drifting or floating sensations
n1
light sleep
n1
Sudden muscle contraction or hypnic myoclonia
n1
n1 duration
10-12 minutes
patient is easily awaken
n1
n1 waves
Alpha, theta, vortex wave
Light sleep, arousal is more difficult
n2
Lower heart rate, blood pressure, respiratory rate, temperature due to the start of energy restoration and relaxed body, snoring may occur
n2
n2 waves
K complex, spindles, theta waves
deep sleep
n3
no eye movement
n3
Vital signs are lowest in this stage, 20-30% lower, O2 consumption is low, very difficult to awaken
n3
stage Important for mental and physical restoration
nrem
Bed-wetting, night terrors, sleep walking, or common sleep disorders may occur
n3
Temporary paralysis of most skeletal muscles, brain metabolism is increased to 20%, breathing rate fluctuates, irregular heart rate, snoring may or may not be present
rem stage
If a person is very tired, REM is ____; more rested, ____ REM
low, higher
rem how many minutes after N1?
70 to 90 minutes
rem duration is only about
5-30 minutes
You can remember dreams in this stage unlike dreams in deep sleep
rem
rem waves
Has theta waves, no delta, k complex, and spindles; has saw tooth pattern
total sleep time of an infant is around
18–20 hours,
mid-adolescence sleep time
(6–8 hours),
During old age, sleep reduces to
5–6 hours/day.
Regarding continuity, infants have _____ and they tend to wake up multiple times.
fragmented sleep
Children often go to bed
early at night
Children often go to bed early at night, however, during adolescence, they develop a
phase delay.
refers to delayed bed-time and wake time.
Phase delay
Aging also influences the _____ of sleep
electrophysiology
Children have a high proportion of _______, which reduces as the person grows old.
N3 (deep sleep)
Sleep is dependent upon two processes:
Homeostatic and Circadian
These processes together decide when we will fall asleep and also the other characteristics of sleep, such as depth, duration, maintenance, and proportion of sleep stages.
Homeostatic and Circadian
the two processes together decide when we will fall asleep and also the other characteristics of sleep, such as
depth, duration, maintenance, and proportion of sleep stages.
also known as “S”
Homeostatic
process makes us feel sleepy depending upon the duration of wakefulness
Homeostatic
The longer the period of wakefulness, the _____ the sleep pressure
higher
this process regulates the proportion of deep sleep (N3 sleep)
homeostatic
this process regulates the proportion of deep sleep (N3 sleep) - the longer the period of wakefulness, the _____ the proportion of deep sleep.
higher
The homeostatic process is dependent upon two major areas of the brain:
VENTROLATERAL PREOPTIC NUCLEUS (VLPO)
MONOAMINERGIC NUCLEI
the sleep-promoting area
VENTROLATERAL PREOPTIC NUCLEUS (VLPO)
which sends inhibitory signals through the GABAergic neurons to the wake-promoting area of the brain.
VENTROLATERAL PREOPTIC NUCLEUS (VLPO)
Wake-promoting area
MONOAMINERGIC NUCLEI
part of the reticular activating system (RAS).
MONOAMINERGIC NUCLEI
The activity of both wake-promoting and sleep-promoting areas is modulated through another group of neurons, _____
the hypocretin neurons
that are present in the lateral and posterior hypothalamus.
the hypocretin neurons
decides whether to sleep or be awake
Hypocretin neurons
modulate the activity of the other two areas of the brain in such a manner that only one state of consciousness, that is, wakefulness or sleep prevails
the hypocretin neurons
Damage to the hypocretin neurons leads to a condition known as
narcolepsy
a person is not able to maintain either states and experiences bouts of sleepiness during wakefulness
narcolepsy
Overwhelming daytime drowsiness, difficulty in staying awake for long periods of time
narcolepsy
known as process “C”
Circadian Process
is dependent upon environmental light.
Circadian Process
Certain other factors can also regulate this process:
• Food
• Emotions
• social activity
• Exercise
Circadian Process
Certain other factors can also regulate circadian process:
• Food
• Emotions
• social activity
• Exercise
Factors that affect the circadian rhythm
zeitgebers
Rhythmically occuring natural phenomenon which acts as a cue in the regulation of the body’s circadian rhythm
zeitgebers
is the strongest factor which can entrain the circadian rhythm.
LIGHT
Environmental light falls on the retina and through the _______ (glutaminergic in nature), it sends signals to the
retinohypothalamic tract (RHT)
suprachiasmatic nucleus (SCN).
The SCN one of the nuclei of hypothalamus and acts as the _____ circadian clock.
‘master clock’
During the dark, SCN sends signals to the ______ to secrete melatonin.
pineal gland
is a hormone that is released into the blood and circulated to the various organs of the body.
Melatonin
responsible for making us sleep
Melatonin
The SCN also sends signals to the VLPO through the _______ and thus can activate it.
dorsomedial hypothalamus (DMH)
In the presence of environmental light, melatonin secretion _______. This is why during the dark, we feel sleepy.
stops
To fall asleep, it is important that both the homeostatic and circadian processes are in the
same phase.
If homeostatic and circadian process are not synchronized, then we may feel
difficulty in falling asleep or staying awake.
factors affecting sleep
age
illness
environment
fatigue
lifestyle
emotional stress
smoking
diet
medication
If patient has weight loss, sleeping time will be
decreased
Hypnotics disrupt _____; lowers ____
N3 and NREM
REM
causes insomnia and nightmares
Beta blockers (anti-hypertensive medications)
can suppress REM stage
Narcotics
characterized by theta waves in EEG; slow eye movement, and diminution of muscle tone
n1
theta waves, sleep spindles, and K complexes in EEG; absent eye movements and low muscle tone
n2
more than 20% of epoch has delta waves
n3
is characterized by low-voltage, mixed-frequency activity in EEG, rapid eye movement, and muscle atonia
rem sleep
normal sleep cycle
awake
n1
n2
n3
n4
n3
n2
rem
n2
These stages follow a characteristic pattern in normal persons where NREM and REM sleep keep alternating at an interval of
90–120 min.
Sleep starts with NREM sleep, and after approximately _____, the first episode of REM sleep appears.
90 min
This cycle continues throughout the night and during a 7–8 h sleep, an average healthy person has _____ cycles of NREM and REM.
4–5
the first half of the night is characterized by a high proportion of
N3 sleep.
REM sleep is regulated by the process “C” and it is predominantly seen during the
second half of the night
Stage of wakefulness, recorded when patient is awake and alert with eyes open
beta
Relatively low voltage or amplitude and a frequency greater than 13 Hz.
beta
Known as “busy waves” of the brain
beta
Relatively high voltage or amplitude and a frequency of 8-13 Hz
alpha
Known as the “relaxed waves” of the brain
alpha
Recorded when individual is awake, but drowsy state, eyes are closed
alpha
Commonly seen during stage 1 sleep and REM stage
alpha
Bursts of alpha waves are seen during briefe awakenings from
sleep-called arousals
Relatively low frequency of 4-7 Hz and low amplitude of 10 micro-volts
theta
Known as “drowsy waves” of the brain
theta
Individual is awake, but relaxed and sleepy
theta
Seen during stage 1, REM and stage 2
theta
Slowest of the four types of brain waves
delta
Frequency of less than 4 Hz and high amplitude (>75 uV) broad waves
delta
Known as the “deep sleep waves”
delta
Associated with a dreamless state, patient is not easily aroused
delta
Seen primarily during N3
delta
Intermittent high-amplitude, biphasic waves of at least 0.5 second duration that signal the start of stage 2 sleep
k complex
Consists of a sharp negative wave (upward deflection) followd by a slower positive wave (downward deflection), that is 0.5 seconds
k complex
Seen during stage 2 and sometimes in stage 3
k complex
are often superimposed on K complexes
Sleep spindles
Sudden bursts of EEG activity in the 12-14 Hz frequency (6 or more distinct waves) and duration of 0.5 to 1.5 seconds
sleep spindles
Mark the onset of stage 2, may be seen in stage 3 and 4 but it does not occur in REM
sleep spindles
Notched-jagged waves, frequency in the theta range (3-7 Hz)
sawtooth
Commonly seen during REM sleep, not part of criteria of REM sleep, but can be used to identify REM
sawtooth
Sharp negative (upward deflection) EEG waves, often in conjunction with high amplitude and short (2-7 Hz) activity
vertex
Amplitude of many vertex sharp waves are greater than 20 uV and may be as high as 200 uV
vertex
Usually seen at end of stage 1
vertex
alpha, theta, vertex
n1
k complex, spindles, theta
n2
delta
n3
theta, sawtooth
REM
Absence of muscle tone during REM sleep (paralysis)
atonia during rem
is characterized by low voltage mixed frequency activity and sawtooth waves in EEG.
rem
REM sleep is modulated by_______situated in the brainstem.
laterodorsal tegmental/ pedunculopontine tegmental (LDT/PPT) cholinergic nuclei
_______ depolarize thalamic neurons leading to cortical activation that is important for _____
laterodorsal tegmental/ pedunculopontine tegmental (LDT/PPT) cholinergic nuclei
generation of dreams.
s in ventomedial medulla that secrete GABA and glycine on the anterior horn cells in spinal cord leading to profound atonia.
GABAergic cell
develops during REM sleep, leading to multiple ramifications that are clinically important.
Profound muscle atonia
by producing atonia in upper airway muscles, in particular,______ it narrows the caliber of the upper airway and increases risks for ______
genioglossus, hypopnea
largest muscle mass that makes up the tongue
genioglossus
sudden muscle weakness when a person is awake),
cataplexy
a sign of nacolepsy
cataplexy
absence of atonia during REM sleep leads to the
REM sleep behavior disorder.
is produced by the _________ in the spinal cord and the _____- on cells of the sub-dorsolateral tegmental nucleus.
atonia
glycine-mediated (glycineric) inhibition of the anterior horn cells
hypoglossal nerve by the REM
