Sleep And Reticular formation ppt 21 Flashcards
What is the reticular formation?
broad region where white matter and gray matter exhibit a netlike arrangement
Superior part of the spinal cord, throughout the brain stem, and into the inferior part of the diencephalon
ascending (sensory) and descending (motor) functions
What does the RAS consist of?
The ascending portion of the reticular formation
sensory axons that project to the cerebral cortex, both directly and through the thalamus
Activation of RAS promotes wakefulness, & inhibition of RAS promotes sleep.
Function of RAS
Consciousness Arousal and Awakening Attention and alertness Regulate muscle tone Regulation of HR, bp, and rr
What are alpha waves on a EEG
Awake & relaxed (eyes closed)
parietal and occipital region
What are the beta waves on a EEG
Awake & Alert (open eyes, busy)
Frontal region
What are the Theta waves on a EEG
Awake children (parietal & temporal region)
emotional stress
light sleep in adult
What are delta waves on a EEG?
Deep Sleep
Infancy
What are the physiological various of age in a EEG?
- Upto 2 years of age- awake EEG- in delta range
- 2-6 years of age- awake EEG- theta range
- Alpha rhythm in relax state in adult
What is a clinical use of EEG
distinguishdifferent types of epileptic seizures
What are the important aspects of sleep?
- Sleep consolidates learning and memory
- Adequate sleep promotes growth, as GH secretion is high during sleep.
What are the two stages of sleep?
NREM- slow EEG, high muscle tone. Idling brain in a movable body
REM- aroused EEG An awake brain in a paralyzed body
What EEG change occurs going from awake to drowsy?
Beta to alpha
What is the EEG characteristic of stage 1?
Physical Characteristics?
Alpha rhythm, is replaced by low frequency & high amplitude EEG waves
low HR and rr
What is the EEG characteristic of stage 2?
Physical Characteristics?
Amplitude of EEG waves slightly increases.
EEG Patterns: Sleep spindles & K-complexes
Eyes are generally still and heart and breathing rates decrease only slightly
What is the EEG characteristic of stage 3?
Physical Characteristics?
Stage of moderately deep sleep.
EEG Patterns: lower frequency & higher amplitude.
What is the EEG characteristic of stage 4?
Physical Characteristics?
- Stage of deep sleep
- EEG Patterns: delta rhythm
- Maximum time of sleep is spent in this stage initial stage of sleep.
- Hardest to arouse
What is the EEG characteristic of stage REM?
Physical Characteristics?
- EEG Patterns: Brust of sawtooth waves or Ponto-geniculo-occipital (PGO) spikes
- Easiest to arouse
What does a sleep cycle consist of?
90min REM and NREM repeated 3-6 times a night.
How do sleep cycles change throughout the night?
Earlier in the night there will be periods of stage 3 and stage 4 sleep, but these diminish towards morning, when there are longer periods of REM sleep and less deep sleep.
What is circadian control?
The suprachiasmatic nucleus (SCN) is the biological clock which is influenced by the light dark cycle through retinohypothalamic pathways.
SCN- Pineal gland- Melatonin
Chemical control for sleep
Sleep: Ach, Parasympathetic, GABA
Awake: NE/Serotonin, HIstamine
Insomnia
Inability to sleep.
Narcolepsy
Day time sleepiness. Cataplecy
Sleep Paralysis
Bruxism
Nocturnal Grinding of Teeth
Nocturnal Enuresis
Bed Wettin
Sleep Apnea
Cessation of airflow at the nose or mouth during sleep.
Last longer than 10 secs each. Pathologic if >5 episodes /hour or >300/night
Hypersomnia
Damage to brainstem RAS.
Patient sleeps for days to weeks continuously
Night Terrors
Parasomnic disorder
Nightmares: usually in children in stage 3 or 4 of NREM sleep
