Ch 42: Sleep Flashcards
What is sleep
Sleep is a cyclical physiological process that alternates with longer periods of wakefulness.
Circadian Rhythm
It influences the pattern of major biological and behavioral functions. People experience cyclical rhythms as part of everyday lives, the most familiar rhythm is the 24-hr day-night cycle known as circadian rhythm or diurnal.
What factors affect circadian rhythm?
light, temperature, social activities, and work routines
Where is the major sleep center in the body?
Hypothalamus. It secretes hypocreatins that promote wakefulness and rapid eye movement sleep.
What hormones control sleep?
Prostaglandin D2, L-tryptophan, and growth factors
whether a person remains awake or falls asleep depends on…
A balance of impulses received from higher centers (thoughts), peripheral sensory receptors (sound or light stimuli), and the limbic system (emotions)
What are the two phases of normal sleep
Nonrapid eye movement (NREM) 4 stages
Rapid eye movement (REM)
What is Stage 1: NREM
- Lasts a few minutes
- It includes lightest level of sleep
- Decreased physiological activity begins with gradual fall in vital signs and metabolism
- Sensory stimuli such as noise easily arouses person
- Awakened, person feels as though daydreaming has occured.
What is Stage 2: NREM
- Lasts 10-20 minutes
- Period of sound sleep
- Relaxation progresses
- Body functions continue to slow
- Arousal remains relatively easy
What is Stage 3: NREM
- Lasts 15-30 minutes
- Involves initial stages of deep sleep
- Muscles are completely relaxed
- Vital signs decline but remain regular
- Sleeper is difficult to arouse and rarely moves
What is Stage 4: NREM
- Lasts ~ 15-30 minutes
- Deepest stage of sleep
- If sleep loss has occurred, sleeper spends considerable portion of night in this stage.
- Vital signs are significantly lower than during waking hours
- Sleepwalking and enuresis (bedwetting) sometimes occur
- Difficult to arouse sleeper
- Body releases human growth hormone for repair and renewal of epithelial and specialized cells (brain)
- Especially important in children, they experience more stage 4 sleep.
What is REM sleep
- Stage usually begins about 90 minutes after sleep has begun
- Duration increases with each sleep cycle and averages 20 minutes
- Vivid, full color, elaborate dreaming occurs; less vivid dreaming occurs in other stages
- Stage is typified by rapidly moving eyes, fluctuating heart and respiratory rates, increased or fluctuating blood pressure, loss of skeletal muscle tone, and increase of gastric secretions.
- Very difficult to arouse sleeper
- Necessary for brain tissue restoration and appears to be important for cognitive restoration
Sleep disorders
Conditions that if untreated generally cause disturbed nighttime sleep that results in one of three problems:
- Insomnia
- Abnormal movements or sensation during sleep or when awakening at night
- Excessive daytime sleepiness (EDS): results in impaired waking function, poor work performance, accidents, and emotional problems.
Sleep Cycle
Presleep lasts 10-30 minutes. Once asleep the person usually passes thru 4 or 5 complete sleep cycles per night, each consisting of four stages of NREM and a period of REM sleep. Each cycle lasts ~ 90-100 minutes. See picture for pattern of stages:42-2 pg 941
Insomnias
Most common sleep complaint, signaling an underlying physical or psychological disorder. Disorders related to difficulty falling asleep. Chronic. Examples:
- Adjustment sleep disorder
- Inadequate sleep hygiene
- Behavioral insomnia of childhood
- Insomnia caused by medical condition
8 Categories of sleep disorders
- Insomnias
- Sleep related Breathing Disorder (Central Sleep Apnea Syndromes
- Hypersomnias Not Caused by sleep related breathing disorder (Narcolepsy)
- Parasomnias (disorders of arousal; ex sleepwalking, sleep terrors) Also, nightmare disorder, sleep related hallucinations, and enuresis.
- Circadian Rhythm Sleep Disorders: Delayed sleep phase, jet lag leg, shift work type.
- Sleep related movement disorders: Restless leg, sleep related bruxism(teeth grinding)
- Isolated symptoms, unresolved issues: Long sleeper, sleep talking
- Other: Physiological and Environmental sleep disorder.
Hypersomnolence
Inadequacies in either quantity or quality of nighttime sleep, causing Excessive Sleepiness
Polysomnogram
Involves use of EEG, EMG, and EoG to monitor stages of sleep and wakefulness during nighttime sleep.
Sleep apnea
Disorder characterized by the lack of airflow through the nose and mouth for periods of 10 sec or longer during sleep. There are 3 types:
- Central- Involves dysfunction in the respiratory control center of the brain. Impulse to breathe fails temporarily. common with brainstem injury, muscular dystrophy
- Obstructive- (Most Common) Risks are obesity and hypertension. Occurs when muscles or structures of the oral cavity or throat relax during sleep. Upper airway becomes part or completely blocked, diminishing or stopping nasal airflow.
- Mixed-
Narcolepsy
Dysfunction of mechanisms that regulate sleep and wake states. Excessive daytime sleepiness is most common complaint. Person falls asleep at inappropriate times.
Parasomnias
Sleep problems more common in children than adults. Somnambulism (sleepwalking), night terrors, nocturnal enuresis (bedwetting), bruxism (teeth grinding)
Sleep requirements by age:
Neonates: ~16 hrs/day
Infants: ~ 15 hrs/day; 8-10 @ night w/ naps
Toddlers: ~ 12 hrs/day
Preschoolers: ~ 12 hrs/day
School Age: ~9-12 hrs; depending on age. average decreases as gets older.
Adolescents: ~ 7.5 hrs/night
Young Adults: 6-8.5 hrs/night
Middle Adults: Amt of stage 4 sleep declines
Older adults: Complaints of sleeping difficulties increase with age.
Factors Influencing Sleep
Drugs, Lifestyle, Usual Sleep patterns, emotional stress, environment, exercise, and fatigue, food and caloric intake.
Tools for Sleep Assessment
Two effective subjective measure of sleep:
- Epworth Sleepiness Scale: evaluates the severity of EDS
- Pittsburgh Sleep Quality Index: assesses sleep quality and sleep patterns.
