Chapters 17 and 18 Sleep/Wake disorders and Thought, Emotion, and Memory Disorders Flashcards
What role does the thalamus play in the sleep-wake cycle? What can it be compared to?
The thalamus can be compared to a switch board. It receives information from the lower neurologic system and relays it to the correct part of the brain. In regard to the sleep/wake cycle, it passes the information to the correct part of the cerebral cortex.
What is the cerebral cortex?
The cerebral cortex is the outer most layer of the cerebrum (the brain). It is divided into the frontal, parietal, occipital, and temporal lobes.
Why is sleep so important to the body’s health?
- Allows the body and mind to recharge.
- Allows the immune system of the brain to “clean and repair”
- Lack of sleep impairs concentration, thinking, and memory processing
What is the needed amount of sleep for adults? What about children and teens?
Adults need 7-9 hours of sleep
Children and teens need more
REM Sleep
1. What changes with body functions occur during REM sleep?
2.. What ANS changes can be seen during REM sleep?
Rapid Eye Movement Sleep
1. REM, loss of muscle movements, vivid dreaming, ANS changes.
2. BP, HR, and RR increase during REM. Cerebral blood flow and metabolic rate decrease during REM sleep.
Non-REM sleep
Quiet type. Inactive but fully regulated brain. Body moveable.
Stage 1 Non-REM sleep
low-voltage, mixed-frequency EEG activity
Occurs at onset of sleep, lasts about 1-7 minutes. Transition between awake and sleep. Easily aroused.
Transitional stage for repeated sleep cycles throughout the night.
Stage 2 Non-REM sleep
Deeper sleep, lasts 10-25 minutes.
EEG shows sleep spindles.
Stage 3-4 Non-REM sleep
Deep sleep, high-voltage, low frequency EEG. difficult to arouse person.
Stage 3 (few minutes) Stage 4 (20-40 minutes)
Muscles of the body relax
Decreased BP, slowed GI activity
Describe the differences in breathing found throughout the stages of sleep
Stage 1 and 2 - waxing and waning of tidal volume. Periods of apnea.
Stage 3 and 4 - regular
REM - irregular breathing, not periodic though. Some apnea spells that are brief.
What controls the circadian cycle?
Hypothalamus - specifically the suprachiasmatic nucleus.
What helps control the circadian cycle?
- Exposure to light/darkness
- Locomotion
- Food
- Glucocorticoids
- Temperature
What is melatonin? What makes it?
The pineal gland synthesizes melatonin. Melatonin is a hormone that produces changes to the circadian rhythm, making the person sleepier.
What stimulates the anterior pituitary gland? What does the anterior pituitary gland control?
The hypothalamus stimulates the AP to release hormones. The hormones released by the AP:
1. Thyroid
2. Growth
3. Cortisol
4. Sex hormones
F - FSH
L - L
A - ACTH
T - TSH
P - Prolactin
I -
G - growth hormone
What is the SCN? What formations does it interact with in the brain?
A small group of hypothalamic cells that regulate the sleep/wake cycle.
Interact with the forebrain, the thalamus, and the hypothalamus.
What does the hypothalamus regulate in regard to sleep/wake?
Temperature and metabolic processes. It also stimulates the AP, brain stem, reticular formation, and the pineal gland.
What does the brain stem and the reticular formation do in regard to sleep/wake?
Regulation of the ANS and along with the hypothalamus, have a direct role in sleep/wake cycles
Slow wave sleep
Non-REM sleep
Dyssomnia
Disorders of initiating and maintaining sleep or excessive sleepiness
Parasomnias
Undesirable phenomena that occur primarily during sleep. Does not interrupt the sleep/wake cycle.
Sleep hygiene
How the persons prepares for going to sleep. Brush teeth, play on phone, watch TV, wind down time are examples.
EOG/ EMG/ ECG/ EEG
These are monitored during a sleep study. EOG - electrooculogram
EMG - electromyogram
ECG - electrocardiogram
EEG - electroencephlagram?
Actigraphy
Measures muscle motion. Useful tool for measuring sleep efficiency outside the sleep labs.
Non-24-hour sleep-wake syndrome
1. What causes this?
2. Who is commonly affected?
When there is lack of synchronization between internal sleep-wake rhythm and the external 24-hour day.
- This is caused by constant exposure to light or darkness that throws off the body’s normal circadian rhythm.
- Blind or nearly blind people commonly struggle with this disorder (2/3 of blind people affected). People with lesions on the SCN.
Narcolepsy
1. Associated symptoms
2. Onset
3. Etiology
Disorder of excessive daytime sleepiness unchanged by getting a full night’s sleep.
1. Cataplexy, hallucinations (hypnagogic hallucinations), sleep paralysis.
2. Typically develops around 15-30 years of age.
3. Abnormality in REM sleep. Genetic components. HLA DQB1.
Cataplexy
sudden muscle weakness
Restless leg syndrome
1. Primary VS secondary causes
RLS - uncomfortable urge to move the limbs. Can manifest as pacing, tossing and turning, rubbing the legs. Urge worsens at night and improve with activity.
1. Primary - thought to have a genetic component
2. Secondary - Iron deficiency, neurologic disease, pregnancy, uremia, and medications.
HLA
Human leukocyte antigen
Central VS obstructive sleep apnea
Central sleep apnea is rare. It is characterized by cessation or decline in ventilation during sleep often resulting in desaturation.
OSA - upper airway obstruction (tongue or other structure) results in decreased airway clearance. There is no decline in respiratory function. Results in excessive daytime sleepiness, snoring, frequent wakings during the night, morning headaches.