Week 9 Sleep - Lecture notes 28-32 PDF

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Sahar Nouredini...

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Functions of sleep: 1. Purpose of sleep a. Remain unclear b. Physiological & psychological restoration i. Non-rapid eye movement sleep contributes to body tissue restoration specifically w/ renewal of epithelial cells as well as specialized cells w/in brain (where cognition & memory ties into sleep) ii. Protein synthesis + cellular division that’s necessary for renewal of tissues like the epithelial cells or bone marrow c. Maintenance of biological functions i. Cardiac function → necessary for brain tissue & cognitive restoration, as well as memory 1. Dreams are often more vivid & elaborate in this stage 2. Some believe that dreams are functionally important for us to learn, memory process, & adapt to stress a. Ability for us to describe a dream and interpret its significance sometimes can help someone resolve personal fears or problems Sleep regulation: - Regulated by CNS activity - Any CNS disturbance can affect sleep - Hypothalamus → secretes hypocretins - Released during periods of wakefulness & bind to specific target neurons that have hypocretins receptors → increase the activity of these receptors ⇒ KEEP US AWAKE - Reticular activating system (RAS) - Releases various catecholamines (ie. norepinephrine) - Maintains our consciousness & arousal after WE’VE WOKEN UP - Activation of the RAS → further begins to decline once the room is dark or quiet

- RAS system still being stimulated if there’s still light/noise that makes it difficult to sleep - Bulbar synchronizing region (BSR) - Takes over once the RAS stimulus has decreased - Causes sleep & in the region of the pons & medulla → release of serotonin from specialized cells that are result in sleep - Homeostatic process (Process S) - Accumulation of sleep-inducing substances within the brain - Internal biochemical system that operates like a timer → generate sleep drive or need to sleep after a certain amount of time being awake - Regulation of the length & depth of sleep - Operates simultaneously w/ circadian rhythm - Helps regulate sleep & wakefulness → cyclical rhythms Circadian rhythm → type of sleep-wake cycle that influences pattern of major biological as well as behavioral function - Frequently become synchronized w/ other body functions (ie. body temp, HR, BP, hormone secretion, mood) - Failure to maintain individual’s normal cycle → can negatively influence their health Sleep cycle process: 1. Wakefulness a. Gradually becomes sleepy (lasts 10-30 minutes) 2. NREM Stage 1 → lighter sleep (easily aroused) 3. NREM Stage 2 → lighter sleep 4. NREM Stage 3 → “slow wave” or deep sleep → 5. NREM Stage 4 6. NREM Stage 3 7. NREM Stage 2 8. REM → reached in about 90 minutes & 75-80% is spent on NREM sleep a. w/ each successive cycle → Stage 3 & 4 shortens & REM sleep lengthens until 60 minutes b. Usually go through 4-5 cycles per night c. REM sleep → more vivid dreams

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Sleep apnea → unable to leave the REM cycle w/ the constant awakenings 9. NREM Stage 2 *older person → spend more time in lighter stages of sleep

Physical illness & sleep: 1. Pain → a. Physical discomfort, anxiety, depression 2. Hypertension → a. Early awakening, fatigue 3. Respiratory disorders → a. Can affect sleep 4. Nocturia → a. Disrupt sleep cycle from the frequent use of the bathroom overnight 5. Restless leg syndrome → a. Occur before onset of sleep → keep the pt awake from sleep i. Recurrent rhythmic movements of the feet & legs 1. Itching sensation that’s deep within their muscles ii. Prevents relaxation leading to inability to sleep

Sleep terminology → 1. Hypersomnolence (daytime sleepiness) 2. Polysomnogram (encephalogram, electromyogram, electro-oculogram) a. EEG → Used to measure electrical activity within the cerebral cortex b. EMG → measure muscle tone during sleep c. EOG → monitor various stages of sleep & wakefulness during sleep 3. Sleep hygiene a. Whether the bed is associated w/ sleep or intercourse → important for falling asleep 4. Cataplexy a. Sudden muscle weakness during intense emotions → associated with narcolepsy 5. Sleep paralysis a. Unable to move/talk → right before or waking up from dream Sleep alterations: 1. Insomnia a. Chronically have difficulty falling asleep 2. Sleep apnea a. Lack of blood flow through the nose and mouth for periods of 10 seconds or longer while asleep b. Types: i. Central (dysfunction in respiratory control center of the brain) 1. Treatment → a. More supportive therapy than curative therapy → provide therapy for underlying cardiac or respiratory complications & emotional problems from sleep deprivation & treatment of brain stem injury ii. Obstructive 1. Treatment → a. Positioning of head, BiPAP/ CPAP, b. Adenoidectomy, uvulectomy, or remodeling c. Leads to unconscious awakenings → complaints of excessive sleepiness in the daytime i. Most intense when wake up & right before going to bed

d. Major risk factors → i. Obesity ii. Hypertension iii. Smoking iv. Enlarged tongue, uvula, short neck, etc 3. Narcolepsy a. Uncontrollable mechanism that makes you fall asleep i. Associated during teenage years ii. Treated with → stimulants & antidepressants (suppress REM symptoms) iii. Recommendation → brief naps no more than 20 minutes / regular exercise / chewing gum 1. Should avoid anything that increases their sleepiness (ie. alcohol, heavy meals, sleep deprivation…) 4. Sleep deprivation a. Difficulty sleeping that can be due to many things (ie. difficulty breathing, pain, emotional, distress, fever, etc) i. Anything that prevents you from sleeping sufficiently b. Can lead to → disorientation, depression, cardiovascular disease, weight gain, blood sugar, cognitive aspect of memory 5. Parasomnia a. Sleep problems more common in children that includes sleepwalking, nightmares (physiologic response to nightmare)...