Sleep Flashcards
Hypnic Jerk
An involuntary muscle twitch that cause a jolt in the body, which occurs during the hypnogogic stage of sleep. Considered to occur in stage 1 NREM
Circadian rhythm
A physical, mental and behavioural pattern that follows a 24-hour cycle such as the sleep wake cycle.
Hypnogram
A graph that represents the stages of sleep that occur throughout the night.
Hypnogogic state
A transitional state that occurs between being awake and asleep. During this state, we may experience hallucinatory images, such as ashes of light and vivid images.
Infradian rhythm
A recurrent cycle that occurs over periods longer than 24 hours such as the menstrual cycle.
Hypnopompic state
A transitional state that occurs between being asleep and waking up.
Muscle Antonia
The total relaxation of muscles to the point of virtual paralysis during REM sleep.
Non rapid eye movement sleep NREM
One of the two major phases of sleep characterised by little or no rapid eye movement. Divided into four stages of NREM sleep that are distinguished by varying brain wave patterns.
Sleep
An altered state of consciousness. A naturally occurring bodily rhythm accompanied by a number of physiological effects.
Rapid eye movement REM sleep
One of the two major phases of sleep that is characterised by rapid jerking eye movements and dreaming. Higher arousal but not awake. Helps consolidate memories - form new connections between neurons, evidence that young have more REM than old as brain still developing. Irregular fast waves, similar to beta. Easier to wake up from
Slow wave sleep
The deepest stage of sleep characterised by the emergence of delta waves that occurs during stages 3 and 4 of NREM sleep.
Ultradian rhythm
A recurrent cycle that is repeated within a 24 cycle (i.e. a cycle that is shorter than 24 hours) such as the REM/NREM cycle.
A typical nights sleep
Approximately 7-8 hours per night
1.5 hour cycles
NREM periods decrease as the night progresses
REM periods increase as the night progresses
REM VS NREM SLEEP
We spend approximately 80% of our sleep time as
adults in NREM and only 20% in REM
Plus photo in favourites
Stages of NREM sleep
Photo in favourites
MULTIPLE PHOTOS, ALL DETAILS
I’m sick, not going to school tomorrow, I will miss swimming again and then the gat is the day after :( or :) ???
Sleep spindle
A sleep spindle is a bust of high frequency brainwaves.
Polysomnography
Detailed monitoring and recording of physiological responses during sleep.
Stage 1 NREM
Stage 1 NREM sleep is brief, lasting around 5 minutes for most people, but it can range from 30 seconds to 10 minutes. It is a very light sleep from which we can be easily awakened. If this happens, we often think we haven’t been asleep at all. It is sometimes called the presleep stage. Mix of alpha and theta waves.
Stage 2 NREM
We spend about 20 minutes in stage 2 NREM sleep in our first NREM/REM sleep cycle and it is still fairly easy to be woken up at this stage. As we slip further into stage 2 NREM sleep, our eyes stop rolling, our muscles become further relaxed and our breathing and heart rate continue to decrease. Theta waves with sleep spindles, high frequency and k complexes.
Stage 3 NREM
Stage 3 NREM sleep is a brief transitional stage that marks the start of deep sleep. During stage 3 NREM sleep, we become less responsive to external stimuli and more difficult to awaken. If we are woken from stage 3 NREM sleep, we feel very groggy and disorientated. In stage 3 NREM sleep, our eyes do not move, our muscles are relaxed and heart and breathing rates continue to become slower and more regular. Mix of theta waves and delta waves.
Stage 4 NREM
The deepest sleep and, as in stage 3 NREM sleep, it is extremely difficult to wake someone who is in this sleep stage. More than 50% delta waves. Although our level of conscious awareness is very low, we can still be sensitive to certain stimuli, such as a baby crying or a smoke alarm. In the first NREM/REM sleep cycle, we spend about 30 minutes in stage 4 NREM sleep.
Waves when awake
Beta waves
Sleep pattern shifts over the lifespan
Most adolescents get about 8 hours. Researchers show that adolescents end 9-10 hours. Many people report not being able to get to sleep quickly, not getting enough sleep and difficulty getting up in the morning. Biological factors - rhythms - regulate when we sleep and wake through the release of hormones that make us tired. Our sleep wake cycle is called a circadian rhythm - about a day.
Level of awareness when asleep
Sleep is a unique state of awareness. It is certainly not a period of being awake, nor are we in a coma. We have very little, awareness of our external environment when we are asleep. External environment may be incorporated in dream. We may suddenly be woken from a deep sleep by something highly personally relevant (such as a parent responding to their baby’s crying).
Content limitations
When we sleep, we relinquish conscious control of our thoughts. Everyone dreams and the dreams we remember tend to be bizarre. The contents of our dreams tend to be much broader and deeper than our thoughts in normal waking consciousness.
Controlled and automatic processes
Performing other tasks is probably impossible. It is interesting to note that most sleep walkers, known as somnambulists, usually carry out routine, automatic processes when they sleep walk.
Perceptual and cognitive distortions
Our attention to sensory stimuli is lowered during sleep, including our perception of pain. Our thoughts are more likely to be disorganised and unrealistic during our dreams. Although most of us dream about four or five times a night we remember little upon awaking.
Emotional awareness
Our emotions can be more or less intense or attened during sleep. A nightmare can make us feel very scared and a good dream can make us feel terriffic. There is some evidence that sleep can help us deal with our emotions
Self-control
Our ability to maintain self-control, including monitoring our own behaviour, is lowered during sleep. For instance, we may snore, grind our teeth or talk during our sleep.
Time orientation
Our ability to perceive time may be affected. Time can seem to fly sometimes and be slower other times,. Despite this, there is growing evidence that suggests we have the ability to estimate the amount of time that has elapsed during sleep. Often, we are able to wake up at a predetermined time without the use of an alarm clock.
Transitioning into REM after NREM 4
Rather than remaining in stage 4 NREM sleep, we quickly cycle back through the sleep stages: stage 4 NREM to stage 3 NREM to stage 2 NREM, then skipping stage 1 NREM and going straight into REM sleep.
Physiological changes during REM
During REM sleep there are marked physiological changes. There are repetitive bursts of rapid eye movement, and heart rate, blood pressure and respiration increase and fluctuate. Body temperature tends to match the surrounding environment and genitals are aroused.
Muscle atonia
Lack of muscle tension during REM. The muscles that move voluntarily, especially those below the neck, are very relaxed to the point of being almost paralysed
